MediaWiki REL1_39
Wikimedia\Rdbms\DBConnRef Class Reference

Helper class used for automatically marking an IDatabase connection as reusable (once it no longer matters which DB domain is selected) and for deferring the actual network connection. More...

Inheritance diagram for Wikimedia\Rdbms\DBConnRef:
Collaboration diagram for Wikimedia\Rdbms\DBConnRef:

Public Member Functions

 __call ( $name, array $arguments)
 
 __construct (ILoadBalancer $lb, $params, $role, &$modcount=0)
 
 __destruct ()
 Clean up the connection when out of scope.
 
 __toString ()
 Get a debugging string that mentions the database type, the ID of this instance, and the ID of any underlying connection resource or driver object if one is present.
 
 addIdentifierQuotes ( $s)
 Escape a SQL identifier (e.g.
 
 addQuotes ( $s)
 Escape and quote a raw value string for use in a SQL query.
 
 affectedRows ()
 Get the number of rows affected by the last write query.
 
 anyChar ()
 Returns a token for buildLike() that denotes a '_' to be used in a LIKE query.
 
 anyString ()
 Returns a token for buildLike() that denotes a '' to be used in a LIKE query.
 
 begin ( $fname=__METHOD__, $mode=IDatabase::TRANSACTION_EXPLICIT)
 Begin a transaction.
 
 bitAnd ( $fieldLeft, $fieldRight)
 
 bitNot ( $field)
 
 bitOr ( $fieldLeft, $fieldRight)
 
 buildConcat ( $stringList)
 Build a concatenation list to feed into a SQL query.
 
 buildExcludedValue ( $column)
 Build a reference to a column value from the conflicting proposed upsert() row.
 
 buildGreatest ( $fields, $values)
 Build a GREATEST function statement comparing columns/values.
 
 buildGroupConcatField ( $delim, $table, $field, $conds='', $join_conds=[])
 Build a GROUP_CONCAT or equivalent statement for a query.
 
 buildIntegerCast ( $field)
 
 buildLeast ( $fields, $values)
 Build a LEAST function statement comparing columns/values.
 
 buildLike ( $param,... $params)
 LIKE statement wrapper.
 
 buildSelectSubquery ( $table, $vars, $conds='', $fname=__METHOD__, $options=[], $join_conds=[])
 Equivalent to IDatabase::selectSQLText() except wraps the result in Subquery.
 
 buildStringCast ( $field)
 
 buildSubstring ( $input, $startPosition, $length=null)
 
 cancelAtomic ( $fname=__METHOD__, AtomicSectionIdentifier $sectionId=null)
 Cancel an atomic section of SQL statements.
 
 clearFlag ( $flag, $remember=self::REMEMBER_NOTHING)
 Clear a flag for this connection.
 
 close ( $fname=__METHOD__)
 Close the database connection.
 
 commit ( $fname=__METHOD__, $flush=self::FLUSHING_ONE)
 Commits a transaction previously started using begin()
 
 conditional ( $cond, $caseTrueExpression, $caseFalseExpression)
 Returns an SQL expression for a simple conditional.
 
 databasesAreIndependent ()
 Returns true if DBs are assumed to be on potentially different servers.
 
 dbSchema ( $schema=null)
 Get/set the db schema.
 
 deadlockLoop (... $args)
 Perform a deadlock-prone transaction.
 
 decodeBlob ( $b)
 Some DBMSs return a special placeholder object representing blob fields in result objects.
 
 decodeExpiry ( $expiry, $format=TS_MW)
 Decode an expiry time into a DBMS independent format.
 
 delete ( $table, $conds, $fname=__METHOD__)
 Delete all rows in a table that match a condition.
 
 deleteJoin ( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname=__METHOD__)
 Delete all rows in a table that match a condition which includes a join.
 
 doAtomicSection ( $fname, callable $callback, $cancelable=self::ATOMIC_NOT_CANCELABLE)
 Perform an atomic section of reversible SQL statements from a callback.
 
 dropTable ( $table, $fname=__METHOD__)
 Delete a table.
 
 duplicateTableStructure ( $oldName, $newName, $temporary=false, $fname=__METHOD__)
 Creates a new table with structure copied from existing table.
 
 encodeBlob ( $b)
 Some DBMSs have a special format for inserting into blob fields, they don't allow simple quoted strings to be inserted.
 
 encodeExpiry ( $expiry)
 Encode an expiry time into the DBMS dependent format.
 
 endAtomic ( $fname=__METHOD__)
 Ends an atomic section of SQL statements.
 
 ensureConnection ()
 Connect to the database if we are not already connected.
 
 estimateRowCount ( $tables, $vars=' *', $conds='', $fname=__METHOD__, $options=[], $join_conds=[])
 Estimate the number of rows in dataset.
 
 explicitTrxActive ()
 Check whether there is a transaction open at the specific request of a caller.
 
 factorConds ( $condsArray)
 Given an array of condition arrays representing an OR list of AND lists, for example:
 
 fieldExists ( $table, $field, $fname=__METHOD__)
 Determines whether a field exists in a table.
 
 fieldInfo ( $table, $field)
 Get information about a field Returns false if the field doesn't exist.
 
 flushSession ( $fname=__METHOD__, $flush=self::FLUSHING_ONE)
 Release important session-level state (named lock, table locks) as post-rollback cleanup.
 
 flushSnapshot ( $fname=__METHOD__, $flush=self::FLUSHING_ONE)
 Commit any transaction but error out if writes or callbacks are pending.
 
 getDBname ()
 Get the current database name; null if there isn't one.
 
 getDomainID ()
 Return the currently selected domain ID.
 
 getFlag ( $flag)
 Returns a boolean whether the flag $flag is set for this connection.
 
 getInfinity ()
 Find out when 'infinity' is.
 
 getLag ()
 Get the amount of replication lag for this database server.
 
 getLBInfo ( $name=null)
 Get properties passed down from the server info array of the load balancer.
 
 getPrimaryPos ()
 Get the position of this primary DB.
 
 getProperty ( $name)
 
 getReferenceRole ()
 
 getReplicaPos ()
 Get the replication position of this replica DB.
 
 getScopedLockAndFlush ( $lockKey, $fname, $timeout)
 Acquire a named lock, flush any transaction, and return an RAII style unlocker object.
 
 getServer ()
 Get the hostname or IP address of the server.
 
 getServerInfo ()
 Get a human-readable string describing the current software version.
 
 getServerName ()
 Get the readable name for the server.
 
 getServerVersion ()
 A string describing the current software version, like from mysql_get_server_info()
 
 getSessionLagStatus ()
 Get the replica DB lag when the current transaction started or a general lag estimate if not transaction is active.
 
 getSoftwareLink ()
 Returns a wikitext style link to the DB's website (e.g.
 
 getTableAliases ()
 Return current table aliases.
 
 getTopologyBasedServerId ()
 Get a non-recycled ID that uniquely identifies this server within the replication topology.
 
 getTopologyRole ()
 Get the replication topology role of this server.
 
 getType ()
 Get the RDBMS type of the server (e.g.
 
 implicitOrderby ()
 Returns true if this database does an implicit order by when the column has an index For example: SELECT page_title FROM page LIMIT 1.
 
 indexExists ( $table, $index, $fname=__METHOD__)
 Determines whether an index exists.
 
 indexUnique ( $table, $index, $fname=__METHOD__)
 Determines if a given index is unique.
 
 insert ( $table, $rows, $fname=__METHOD__, $options=[])
 Insert row(s) into a table, in the provided order.
 
 insertId ()
 Get the inserted value of an auto-increment row.
 
 insertSelect ( $destTable, $srcTable, $varMap, $conds, $fname=__METHOD__, $insertOptions=[], $selectOptions=[], $selectJoinConds=[])
 INSERT SELECT wrapper.
 
 isOpen ()
 
 isReadOnly ()
 
 lastDoneWrites ()
 Get the last time the connection may have been used for a write query.
 
 lastErrno ()
 Get the RDBMS-specific error code from the last query statement.
 
 lastError ()
 Get the RDBMS-specific error description from the last query statement.
 
 lastQuery ()
 Get the last query that sent on account of IDatabase::query()
 
 limitResult ( $sql, $limit, $offset=false)
 Construct a LIMIT query with optional offset.
 
 listTables ( $prefix=null, $fname=__METHOD__)
 List all tables on the database.
 
 listViews ( $prefix=null, $fname=__METHOD__)
 Lists all the VIEWs in the database.
 
 lock ( $lockName, $method, $timeout=5, $flags=0)
 Acquire a named lock.
 
 lockForUpdate ( $table, $conds='', $fname=__METHOD__, $options=[], $join_conds=[])
 Lock all rows meeting the given conditions/options FOR UPDATE.
 
 lockIsFree ( $lockName, $method)
 Check to see if a named lock is not locked by any thread (non-blocking)
 
 makeList (array $a, $mode=self::LIST_COMMA)
 Makes an encoded list of strings from an array.
 
 makeWhereFrom2d ( $data, $baseKey, $subKey)
 Build a partial where clause from a 2-d array such as used for LinkBatch.
 
 namedLocksEnqueue ()
 Check to see if a named lock used by lock() use blocking queues.
 
 newSelectQueryBuilder ()
 Create an empty SelectQueryBuilder which can be used to run queries against this connection.
 
 nextSequenceValue ( $seqName)
 Deprecated method, calls should be removed.
 
 onAtomicSectionCancel (callable $callback, $fname=__METHOD__)
 Run a callback when the atomic section is cancelled.
 
 onTransactionCommitOrIdle (callable $callback, $fname=__METHOD__)
 Run a callback when the current transaction commits or now if there is none.
 
 onTransactionPreCommitOrIdle (callable $callback, $fname=__METHOD__)
 Run a callback before the current transaction commits or now if there is none.
 
 onTransactionResolution (callable $callback, $fname=__METHOD__)
 Run a callback when the current transaction commits or rolls back.
 
 pendingWriteCallers ()
 Get the list of method names that did write queries for this transaction.
 
 pendingWriteQueryDuration ( $type=self::ESTIMATE_TOTAL)
 Get the time spend running write queries for this transaction.
 
 ping (&$rtt=null)
 Ping the server and try to reconnect if it there is no connection.
 
 primaryPosWait (DBPrimaryPos $pos, $timeout)
 Wait for the replica DB to catch up to a given primary DB position.
 
 query ( $sql, $fname=__METHOD__, $flags=0)
 Run an SQL query statement and return the result.
 
 queryMulti (array $sqls, string $fname=__METHOD__, int $flags=0, ?string $summarySql=null)
 Run a batch of SQL query statements and return the results.
 
 replace ( $table, $uniqueKeys, $rows, $fname=__METHOD__)
 Insert row(s) into a table, in the provided order, while deleting conflicting rows.
 
 restoreFlags ( $state=self::RESTORE_PRIOR)
 Restore the flags to their prior state before the last setFlag/clearFlag call.
 
 rollback ( $fname=__METHOD__, $flush=self::FLUSHING_ONE)
 Rollback a transaction previously started using begin()
 
 select ( $table, $vars, $conds='', $fname=__METHOD__, $options=[], $join_conds=[])
 Execute a SELECT query constructed using the various parameters provided.
 
 selectDB ( $db)
 Change the current database.
 
 selectDomain ( $domain)
 Set the current domain (database, schema, and table prefix)
 
 selectField ( $table, $var, $cond='', $fname=__METHOD__, $options=[], $join_conds=[])
 A SELECT wrapper which returns a single field from a single result row.
 
 selectFieldValues ( $table, $var, $cond='', $fname=__METHOD__, $options=[], $join_conds=[])
 A SELECT wrapper which returns a list of single field values from result rows.
 
 selectRow ( $table, $vars, $conds, $fname=__METHOD__, $options=[], $join_conds=[])
 Wrapper to IDatabase::select() that only fetches one row (via LIMIT)
 
 selectRowCount ( $tables, $vars=' *', $conds='', $fname=__METHOD__, $options=[], $join_conds=[])
 Get the number of rows in dataset.
 
 selectSQLText ( $table, $vars, $conds='', $fname=__METHOD__, $options=[], $join_conds=[])
 Take the same arguments as IDatabase::select() and return the SQL it would use.
 
 serverIsReadOnly ()
 
 setBigSelects ( $value=true)
 Allow or deny "big selects" for this session only.
 
 setFlag ( $flag, $remember=self::REMEMBER_NOTHING)
 Set a flag for this connection.
 
 setIndexAliases (array $aliases)
 Convert certain index names to alternative names before querying the DB.
 
 setLBInfo ( $nameOrArray, $value=null)
 Set the entire array or a particular key of the managing load balancer info array.
 
 setSchemaVars ( $vars)
 Set schema variables to be used when streaming commands from SQL files or stdin.
 
 setSessionOptions (array $options)
 Override database's default behavior.
 
 setTableAliases (array $aliases)
 Make certain table names use their own database, schema, and table prefix when passed into SQL queries pre-escaped and without a qualified database name.
 
 setTransactionListener ( $name, callable $callback=null)
 Run a callback after each time any transaction commits or rolls back.
 
 sourceFile ( $filename, callable $lineCallback=null, callable $resultCallback=null, $fname=false, callable $inputCallback=null)
 Read and execute SQL commands from a file.
 
 sourceStream ( $fp, callable $lineCallback=null, callable $resultCallback=null, $fname=__METHOD__, callable $inputCallback=null)
 Read and execute commands from an open file handle.
 
 startAtomic ( $fname=__METHOD__, $cancelable=IDatabase::ATOMIC_NOT_CANCELABLE)
 Begin an atomic section of SQL statements.
 
 streamStatementEnd (&$sql, &$newLine)
 Called by sourceStream() to check if we've reached a statement end.
 
 strreplace ( $orig, $old, $new)
 Returns a SQL expression for simple string replacement (e.g.
 
 tableExists ( $table, $fname=__METHOD__)
 Query whether a given table exists.
 
 tableName ( $name, $format='quoted')
 Format a table name ready for use in constructing an SQL query.
 
 tableNames (... $tables)
 Fetch a number of table names into an associative array.
 
 tableNamesN (... $tables)
 Fetch a number of table names into a zero-indexed numerical array.
 
 tablePrefix ( $prefix=null)
 Get/set the table prefix.
 
 textFieldSize ( $table, $field)
 Returns the size of a text field, or -1 for "unlimited".
 
 timestamp ( $ts=0)
 Convert a timestamp in one of the formats accepted by ConvertibleTimestamp to the format used for inserting into timestamp fields in this DBMS.
 
 timestampOrNull ( $ts=null)
 Convert a timestamp in one of the formats accepted by ConvertibleTimestamp to the format used for inserting into timestamp fields in this DBMS.
 
 truncate ( $tables, $fname=__METHOD__)
 Delete all data in a table(s) and reset any sequences owned by that table(s)
 
 trxLevel ()
 Gets the current transaction level.
 
 trxTimestamp ()
 Get the UNIX timestamp of the time that the transaction was established.
 
 unionConditionPermutations ( $table, $vars, array $permute_conds, $extra_conds='', $fname=__METHOD__, $options=[], $join_conds=[])
 Construct a UNION query for permutations of conditions.
 
 unionQueries ( $sqls, $all)
 Construct a UNION query.
 
 unionSupportsOrderAndLimit ()
 Determine if the RDBMS supports ORDER BY and LIMIT for separate subqueries within UNION.
 
 unlock ( $lockName, $method)
 Release a lock.
 
 update ( $table, $set, $conds, $fname=__METHOD__, $options=[])
 Update all rows in a table that match a given condition.
 
 upsert ( $table, array $rows, $uniqueKeys, array $set, $fname=__METHOD__)
 Upsert row(s) into a table, in the provided order, while updating conflicting rows.
 
 wasConnectionLoss ()
 Determines if the last query error was due to a dropped connection.
 
 wasDeadlock ()
 Determines if the last failure was due to a deadlock.
 
 wasErrorReissuable ()
 Determines if the last query error was due to something outside of the query itself.
 
 wasLockTimeout ()
 Determines if the last failure was due to a lock timeout.
 
 wasReadOnlyError ()
 Determines if the last failure was due to the database being read-only.
 
 writesOrCallbacksPending ()
 Whether there is a transaction open with either possible write queries or unresolved pre-commit/commit/resolution callbacks pending.
 
 writesPending ()
 
- Public Member Functions inherited from Wikimedia\Rdbms\Platform\ISQLPlatform
 buildSubString ( $input, $startPosition, $length=null)
 Build a SUBSTRING function.
 

Protected Member Functions

 assertRoleAllowsWrites ()
 Error out if the role is not DB_PRIMARY.
 
 getDomainChangeException ()
 
 normalizeServerIndex ( $i)
 

Additional Inherited Members

- Public Attributes inherited from Wikimedia\Rdbms\IDatabase
const LOCK_TIMESTAMP = 1
 Flag to return the lock acquisition timestamp (null if not acquired)
 
- Public Attributes inherited from Wikimedia\Rdbms\Platform\ISQLPlatform
const QUERY_PSEUDO_PERMANENT = 2
 Track a TEMPORARY table CREATE as if it was for a permanent table (for testing)
 

Detailed Description

Helper class used for automatically marking an IDatabase connection as reusable (once it no longer matters which DB domain is selected) and for deferring the actual network connection.

This uses an RAII-style pattern where calling code is expected to keep the returned reference handle as a function variable that falls out of scope when no longer needed. This avoids the need for matching reuseConnection() calls for every "return" statement as well as the tedious use of try/finally.

Example:
function getRowData() {
$conn = $this->lb->getConnectedRef( DB_REPLICA );
$row = $conn->select( ... );
return $row ? (array)$row : false;
// $conn falls out of scope and $this->lb->reuseConnection() gets called
}
const DB_REPLICA
Definition defines.php:26
Since
1.22

Definition at line 29 of file DBConnRef.php.

Constructor & Destructor Documentation

◆ __construct()

Wikimedia\Rdbms\DBConnRef::__construct ( ILoadBalancer $lb,
$params,
$role,
& $modcount = 0 )
Access: internal
May not be used outside Rdbms LoadBalancer
Parameters
ILoadBalancer$lbConnection manager for $conn
array$params[server index, query groups, domain, flags]
int$roleThe type of connection asked for; one of DB_PRIMARY/DB_REPLICA
null | int&$modcountReference to a modification counter. This is for LoadBalancer::reconfigure to indicate that a new connection should be acquired.

Definition at line 64 of file DBConnRef.php.

◆ __destruct()

Wikimedia\Rdbms\DBConnRef::__destruct ( )

Clean up the connection when out of scope.

Definition at line 923 of file DBConnRef.php.

Member Function Documentation

◆ __call()

Wikimedia\Rdbms\DBConnRef::__call ( $name,
array $arguments )

◆ __toString()

Wikimedia\Rdbms\DBConnRef::__toString ( )

Get a debugging string that mentions the database type, the ID of this instance, and the ID of any underlying connection resource or driver object if one is present.

Returns
string "<db type> object #<X>" or "<db type> object #<X> (resource/handle id #<Y>)"
Since
1.34

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 872 of file DBConnRef.php.

◆ addIdentifierQuotes()

Wikimedia\Rdbms\DBConnRef::addIdentifierQuotes ( $s)

Escape a SQL identifier (e.g.

table, column, database) for use in a SQL query

Depending on the database this will either be backticks or "double quotes"

Parameters
string$s
Returns
string
Since
1.33

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 503 of file DBConnRef.php.

◆ addQuotes()

Wikimedia\Rdbms\DBConnRef::addQuotes ( $s)

Escape and quote a raw value string for use in a SQL query.

Parameters
string | int | float | null | bool | Blob$s
Returns
string

Implements Wikimedia\Rdbms\Database\DbQuoter.

Definition at line 499 of file DBConnRef.php.

◆ affectedRows()

Wikimedia\Rdbms\DBConnRef::affectedRows ( )

Get the number of rows affected by the last write query.

Similar to https://www.php.net/mysql_affected_rows but includes rows matched but not changed (ie. an UPDATE which sets all fields to the same value they already have). To get the old mysql_affected_rows behavior, include non-equality of the fields in WHERE.

Returns
int

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 271 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ anyChar()

Wikimedia\Rdbms\DBConnRef::anyChar ( )

Returns a token for buildLike() that denotes a '_' to be used in a LIKE query.

Returns
LikeMatch

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 511 of file DBConnRef.php.

◆ anyString()

Wikimedia\Rdbms\DBConnRef::anyString ( )

Returns a token for buildLike() that denotes a '' to be used in a LIKE query.

Returns
LikeMatch

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 515 of file DBConnRef.php.

◆ assertRoleAllowsWrites()

Wikimedia\Rdbms\DBConnRef::assertRoleAllowsWrites ( )
protected

Error out if the role is not DB_PRIMARY.

Note that the underlying connection may or may not itself be read-only. It could even be to a writable primary (both server-side and to the application). This error is meant for the case when a DB_REPLICA handle was requested but a a write was attempted on that handle regardless.

In configurations where the primary DB has some generic read load or is the only server, DB_PRIMARY/DB_REPLICA will sometimes (or always) use the same connection to the primary DB. This does not effect the role of DBConnRef instances.

Exceptions
DBReadOnlyRoleError

Definition at line 893 of file DBConnRef.php.

◆ begin()

Wikimedia\Rdbms\DBConnRef::begin ( $fname = __METHOD__,
$mode = IDatabase::TRANSACTION_EXPLICIT )

Begin a transaction.

Only call this from code with outer transaction scope. See https://www.mediawiki.org/wiki/Database_transactions for details. Nesting of transactions is not supported.

Note that when the DBO_TRX flag is set (which is usually the case for web requests, but not for maintenance scripts), any previous database query will have started a transaction automatically.

Nesting of transactions is not supported. Attempts to nest transactions will cause a warning, unless the current transaction was started automatically because of the DBO_TRX flag.

Parameters
string$fnameCalling function name
string$modeA situationally valid IDatabase::TRANSACTION_* constant [optional]
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 668 of file DBConnRef.php.

◆ bitAnd()

Wikimedia\Rdbms\DBConnRef::bitAnd ( $fieldLeft,
$fieldRight )
Parameters
string | int$fieldLeft
string | int$fieldRight
Returns
string

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 407 of file DBConnRef.php.

◆ bitNot()

Wikimedia\Rdbms\DBConnRef::bitNot ( $field)
Parameters
string | int$field
Returns
string

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 403 of file DBConnRef.php.

◆ bitOr()

Wikimedia\Rdbms\DBConnRef::bitOr ( $fieldLeft,
$fieldRight )
Parameters
string | int$fieldLeft
string | int$fieldRight
Returns
string

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 411 of file DBConnRef.php.

◆ buildConcat()

Wikimedia\Rdbms\DBConnRef::buildConcat ( $stringList)

Build a concatenation list to feed into a SQL query.

Parameters
string[]$stringListRaw SQL expression list; caller is responsible for escaping
Returns
string

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 415 of file DBConnRef.php.

◆ buildExcludedValue()

Wikimedia\Rdbms\DBConnRef::buildExcludedValue ( $column)

Build a reference to a column value from the conflicting proposed upsert() row.

The reference comes in the form of an alias, function, or parenthesized SQL expression. It can be used in upsert() SET expressions to handle the merging of column values between each conflicting pair of existing and proposed rows. Such proposed rows are said to have been "excluded" from insertion in favor of updating the existing row.

This is useful for multi-row upserts() since the proposed values cannot just be included as literals in the SET expressions.

See also
IDatabase::upsert()
Parameters
string$columnColumn name
Returns
string SQL expression returning a scalar
Since
1.39

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 445 of file DBConnRef.php.

◆ buildGreatest()

Wikimedia\Rdbms\DBConnRef::buildGreatest ( $fields,
$values )

Build a GREATEST function statement comparing columns/values.

Integer and float values in $values will not be quoted

If $fields is an array, then each value with a string key is treated as an expression (which must be manually quoted); such string keys do not appear in the SQL and are only descriptive aliases.

Parameters
string | string[]$fieldsName(s) of column(s) with values to compare
string | int | float | string[] | int[] | float[]$valuesValues to compare
Returns
mixed
Since
1.35 in IDatabase, moved to ISQLPlatform in 1.39

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 425 of file DBConnRef.php.

◆ buildGroupConcatField()

Wikimedia\Rdbms\DBConnRef::buildGroupConcatField ( $delim,
$table,
$field,
$conds = '',
$join_conds = [] )

Build a GROUP_CONCAT or equivalent statement for a query.

This is useful for combining a field for several rows into a single string. NULL values will not appear in the output, duplicated values will appear, and the resulting delimiter-separated values have no defined sort order. Code using the results may need to use the PHP unique() or sort() methods.

Parameters
string$delimGlue to bind the results together
string | array$tableTable name
string$fieldField name
string | array$condsConditions
string | array$join_condsJoin conditions
Returns
string SQL text
Since
1.23

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 419 of file DBConnRef.php.

◆ buildIntegerCast()

Wikimedia\Rdbms\DBConnRef::buildIntegerCast ( $field)
Parameters
string$fieldField or column to cast
Returns
string
Since
1.31 in IDatabase, moved to ISQLPlatform in 1.39

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 441 of file DBConnRef.php.

◆ buildLeast()

Wikimedia\Rdbms\DBConnRef::buildLeast ( $fields,
$values )

Build a LEAST function statement comparing columns/values.

Integer and float values in $values will not be quoted

If $fields is an array, then each value with a string key is treated as an expression (which must be manually quoted); such string keys do not appear in the SQL and are only descriptive aliases.

Parameters
string | string[]$fieldsName(s) of column(s) with values to compare
string | int | float | string[] | int[] | float[]$valuesValues to compare
Returns
mixed
Since
1.35 in IDatabase, moved to ISQLPlatform in 1.39

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 429 of file DBConnRef.php.

◆ buildLike()

Wikimedia\Rdbms\DBConnRef::buildLike ( $param,
$params )

LIKE statement wrapper.

This takes a variable-length argument list with parts of pattern to match containing either string literals that will be escaped or tokens returned by anyChar() or anyString(). Alternatively, the function could be provided with an array of aforementioned parameters.

Example: $dbr->buildLike( 'My_page_title/', $dbr->anyString() ) returns a LIKE clause that searches for subpages of 'My page title'. Alternatively: $pattern = [ 'My_page_title/', $dbr->anyString() ]; $query .= $dbr->buildLike( $pattern );

Since
1.16 in IDatabase, moved to ISQLPlatform in 1.39
Parameters
array[] | string | LikeMatch$param
string|LikeMatch...$params
Returns
string Fully built LIKE statement

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 507 of file DBConnRef.php.

◆ buildSelectSubquery()

Wikimedia\Rdbms\DBConnRef::buildSelectSubquery ( $table,
$vars,
$conds = '',
$fname = __METHOD__,
$options = [],
$join_conds = [] )

Equivalent to IDatabase::selectSQLText() except wraps the result in Subquery.

See also
IDatabase::selectSQLText()
Parameters
string | array$tableTable name
string | array$varsField names
string | array$condsConditions
string$fnameCaller function name
string | array$optionsQuery options
string | array$join_condsJoin conditions
Returns
Subquery
Since
1.31

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 449 of file DBConnRef.php.

◆ buildStringCast()

Wikimedia\Rdbms\DBConnRef::buildStringCast ( $field)
Parameters
string$fieldField or column to cast
Returns
string
Since
1.28 in IDatabase, moved to ISQLPlatform in 1.39

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 437 of file DBConnRef.php.

◆ buildSubstring()

Wikimedia\Rdbms\DBConnRef::buildSubstring ( $input,
$startPosition,
$length = null )

Definition at line 433 of file DBConnRef.php.

◆ cancelAtomic()

Wikimedia\Rdbms\DBConnRef::cancelAtomic ( $fname = __METHOD__,
AtomicSectionIdentifier $sectionId = null )

Cancel an atomic section of SQL statements.

This will roll back only the statements executed since the start of the most recent atomic section, and close that section. If a transaction was open before the corresponding startAtomic() call, any statements before that call are not rolled back and the transaction remains open. If the corresponding startAtomic() implicitly started a transaction, that transaction is rolled back.

Note
callers must use additional measures for situations involving two or more (peer) transactions (e.g. updating two database servers at once). The transaction and savepoint logic of startAtomic() are bound to specific IDatabase instances.

Note that a call to IDatabase::rollback() will also roll back any open atomic sections.

Note
As a micro-optimization to save a few DB calls, this method may only be called when startAtomic() was called with the ATOMIC_CANCELABLE flag.
Since
1.31
See also
IDatabase::startAtomic
Parameters
string$fname
AtomicSectionIdentifier | null$sectionIdSection ID from startAtomic(); passing this enables cancellation of unclosed nested sections [optional]
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 656 of file DBConnRef.php.

◆ clearFlag()

Wikimedia\Rdbms\DBConnRef::clearFlag ( $flag,
$remember = self::REMEMBER_NOTHING )

Clear a flag for this connection.

Parameters
int$flagOne of (IDatabase::DBO_DEBUG, IDatabase::DBO_TRX)
string$rememberIDatabase::REMEMBER_* constant [default: REMEMBER_NOTHING]

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 220 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ close()

Wikimedia\Rdbms\DBConnRef::close ( $fname = __METHOD__)

Close the database connection.

This should only be called after any transactions have been resolved, aside from read-only automatic transactions (assuming no callbacks are registered). If a transaction is still open anyway, it will be rolled back.

Access: internal
Only for use by LoadBalancer
Parameters
string$fnameCaller name
Returns
bool Success
Exceptions
DBError

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 283 of file DBConnRef.php.

◆ commit()

Wikimedia\Rdbms\DBConnRef::commit ( $fname = __METHOD__,
$flush = self::FLUSHING_ONE )

Commits a transaction previously started using begin()

If no transaction is in progress, a warning is issued.

Only call this from code with outer transaction scope. See https://www.mediawiki.org/wiki/Database_transactions for details. Nesting of transactions is not supported.

Parameters
string$fname
string$flushFlush flag, set to situationally valid IDatabase::FLUSHING_* constant to disable warnings about explicitly committing implicit transactions, or calling commit when no transaction is in progress. This will trigger an exception if there is an ongoing explicit transaction. Only set the flush flag if you are sure that these warnings are not applicable, and no explicit transactions are open.
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 672 of file DBConnRef.php.

◆ conditional()

Wikimedia\Rdbms\DBConnRef::conditional ( $cond,
$caseTrueExpression,
$caseFalseExpression )

Returns an SQL expression for a simple conditional.

This doesn't need to be overridden unless CASE isn't supported in the RDBMS.

Parameters
string | array$condSQL condition expression (yields a boolean)
string$caseTrueExpressionSQL expression to return when the condition is true
string$caseFalseExpressionSQL expression to return when the condition is false
Returns
string SQL fragment

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 577 of file DBConnRef.php.

◆ databasesAreIndependent()

Wikimedia\Rdbms\DBConnRef::databasesAreIndependent ( )

Returns true if DBs are assumed to be on potentially different servers.

In systems like mysql/mariadb, different databases can easily be referenced on a single connection merely by name, even in a single query via JOIN. On the other hand, Postgres treats databases as logically separate, with different database users, requiring special mechanisms like postgres_fdw to "mount" foreign DBs. This is true even among DBs on the same server. Changing the selected database via selectDomain() requires a new connection.

Returns
bool
Since
1.29

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 456 of file DBConnRef.php.

◆ dbSchema()

Wikimedia\Rdbms\DBConnRef::dbSchema ( $schema = null)

Get/set the db schema.

Parameters
string | null$schemaThe database schema to set, or omitted to leave it unchanged
Returns
string The previous db schema

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 156 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call(), Wikimedia\Rdbms\DBConnRef\getDomainChangeException(), and Wikimedia\Rdbms\DatabaseDomain\newFromId().

◆ deadlockLoop()

Wikimedia\Rdbms\DBConnRef::deadlockLoop ( $args)

Perform a deadlock-prone transaction.

This function invokes a callback function to perform a set of write queries. If a deadlock occurs during the processing, the transaction will be rolled back and the callback function will be called again.

Avoid using this method outside of Job or Maintenance classes.

Usage: $dbw->deadlockLoop( callback, ... );

Extra arguments are passed through to the specified callback function. This method requires that no transactions are already active to avoid causing premature commits or exceptions.

Returns whatever the callback function returned on its successful, iteration, or false on error, for example if the retry limit was reached.

Parameters
mixed...$args
Returns
mixed
Exceptions
DBUnexpectedError
Exception

Implements Wikimedia\Rdbms\IMaintainableDatabase.

Definition at line 834 of file DBConnRef.php.

◆ decodeBlob()

Wikimedia\Rdbms\DBConnRef::decodeBlob ( $b)

Some DBMSs return a special placeholder object representing blob fields in result objects.

Pass the object through this function to return the original string.

Parameters
string | Blob$b
Returns
string
Exceptions
DBError

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 714 of file DBConnRef.php.

◆ decodeExpiry()

Wikimedia\Rdbms\DBConnRef::decodeExpiry ( $expiry,
$format = TS_MW )

Decode an expiry time into a DBMS independent format.

Parameters
string$expiryDB timestamp field value for expiry
int$formatTS_* constant, defaults to TS_MW
Returns
string

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 762 of file DBConnRef.php.

◆ delete()

Wikimedia\Rdbms\DBConnRef::delete ( $table,
$conds,
$fname = __METHOD__ )

Delete all rows in a table that match a condition.

Parameters
string$tableTable name
string | array$condsArray of conditions. See $conds in IDatabase::select() In order to prevent possible performance or replication issues or damaging a data accidentally, an empty condition for 'delete' queries isn't allowed. IDatabase::ALL_ROWS should be passed explicitly in order to delete all rows.
string$fnameName of the calling function
Returns
bool Return true if no exception was thrown (deprecated since 1.33)
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 547 of file DBConnRef.php.

◆ deleteJoin()

Wikimedia\Rdbms\DBConnRef::deleteJoin ( $delTable,
$joinTable,
$delVar,
$joinVar,
$conds,
$fname = __METHOD__ )

Delete all rows in a table that match a condition which includes a join.

For safety, an empty $conds will not delete everything. If you want to delete all rows where the join condition matches, set $conds=IDatabase::ALL_ROWS.

DO NOT put the join condition in $conds.

Parameters
string$delTableThe table to delete from.
string$joinTableThe other table.
string$delVarThe variable to join on, in the first table.
string$joinVarThe variable to join on, in the second table.
array | string$condsCondition array of field names mapped to variables, ANDed together in the WHERE clause
string$fnameCalling function name (use METHOD) for logs/profiling
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 539 of file DBConnRef.php.

◆ doAtomicSection()

Wikimedia\Rdbms\DBConnRef::doAtomicSection ( $fname,
callable $callback,
$cancelable = self::ATOMIC_NOT_CANCELABLE )

Perform an atomic section of reversible SQL statements from a callback.

The $callback takes the following arguments:

  • This database object
  • The value of $fname

This will execute the callback inside a pair of startAtomic()/endAtomic() calls. If any exception occurs during execution of the callback, it will be handled as follows:

  • If $cancelable is ATOMIC_CANCELABLE, cancelAtomic() will be called to back out any (and only) statements executed during the atomic section. If that succeeds, then the exception will be re-thrown; if it fails, then a different exception will be thrown and any further query attempts will fail until rollback() is called.
  • If $cancelable is ATOMIC_NOT_CANCELABLE, cancelAtomic() will be called to mark the end of the section and the error will be re-thrown. Any further query attempts will fail until rollback() is called.

This method is convenient for letting calls to the caller of this method be wrapped in a try/catch blocks for exception types that imply that the caller failed but was able to properly discard the changes it made in the transaction. This method can be an alternative to explicit calls to startAtomic()/endAtomic()/cancelAtomic().

Example usage, "RecordStore::save" method:

$dbw->doAtomicSection( __METHOD__, function ( $dbw ) use ( $record ) {
// Create new record metadata row
$dbw->insert( 'records', $record->toArray(), __METHOD__ );
// Figure out where to store the data based on the new row's ID
$path = $this->recordDirectory . '/' . $dbw->insertId();
// Write the record data to the storage system;
// blob store throws StoreFailureException on failure
$this->blobStore->create( $path, $record->getJSON() );
// Try to cleanup files orphaned by transaction rollback
$dbw->onTransactionResolution(
function ( $type ) use ( $path ) {
if ( $type === IDatabase::TRIGGER_ROLLBACK ) {
$this->blobStore->delete( $path );
}
},
__METHOD__
);
}, $dbw::ATOMIC_CANCELABLE );

Example usage, caller of the "RecordStore::save" method:

$dbw->startAtomic( __METHOD__ );
// ...various SQL writes happen...
try {
$recordStore->save( $record );
} catch ( StoreFailureException $e ) {
// ...various SQL writes happen...
}
// ...various SQL writes happen...
$dbw->endAtomic( __METHOD__ );
See also
Database::startAtomic
Database::endAtomic
Database::cancelAtomic
Parameters
string$fnameCaller name (usually METHOD)
callable$callbackCallback that issues DB updates
string$cancelablePass self::ATOMIC_CANCELABLE to use a savepoint and enable self::cancelAtomic() for this section.
Returns
mixed Result of the callback (since 1.28)
Exceptions
DBErrorIf an error occurs, {
See also
query}
Exceptions
ExceptionIf an error occurs in the callback
Since
1.27; prior to 1.31 this did a rollback() instead of cancelAtomic(), and assumed no callers up the stack would ever try to catch the exception.

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 661 of file DBConnRef.php.

◆ dropTable()

Wikimedia\Rdbms\DBConnRef::dropTable ( $table,
$fname = __METHOD__ )

Delete a table.

Parameters
string$table
string$fname
Returns
bool Whether the table already existed
Exceptions
DBErrorIf an error occurs

Implements Wikimedia\Rdbms\IMaintainableDatabase.

Definition at line 822 of file DBConnRef.php.

◆ duplicateTableStructure()

Wikimedia\Rdbms\DBConnRef::duplicateTableStructure ( $oldName,
$newName,
$temporary = false,
$fname = __METHOD__ )

Creates a new table with structure copied from existing table.

Note that unlike most database abstraction functions, this function does not automatically append database prefix, because it works at a lower abstraction level. The table names passed to this function shall not be quoted (this function calls addIdentifierQuotes() when needed).

Parameters
string$oldNameName of table whose structure should be copied
string$newNameName of table to be created
bool$temporaryWhether the new table should be temporary
string$fnameCalling function name
Returns
bool True if operation was successful
Exceptions
RuntimeException

Implements Wikimedia\Rdbms\IMaintainableDatabase.

Definition at line 852 of file DBConnRef.php.

◆ encodeBlob()

Wikimedia\Rdbms\DBConnRef::encodeBlob ( $b)

Some DBMSs have a special format for inserting into blob fields, they don't allow simple quoted strings to be inserted.

To insert into such a field, pass the data through this function before passing it to IDatabase::insert().

Parameters
string$b
Returns
string|Blob
Exceptions
DBError

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 710 of file DBConnRef.php.

◆ encodeExpiry()

Wikimedia\Rdbms\DBConnRef::encodeExpiry ( $expiry)

Encode an expiry time into the DBMS dependent format.

Parameters
string$expiryTimestamp for expiry, or the 'infinity' string
Returns
string

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 758 of file DBConnRef.php.

◆ endAtomic()

Wikimedia\Rdbms\DBConnRef::endAtomic ( $fname = __METHOD__)

Ends an atomic section of SQL statements.

Ends the next section of atomic SQL statements and commits the transaction if necessary.

Since
1.23
See also
IDatabase::startAtomic
Parameters
string$fname
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 651 of file DBConnRef.php.

◆ ensureConnection()

Wikimedia\Rdbms\DBConnRef::ensureConnection ( )

Connect to the database if we are not already connected.

Definition at line 81 of file DBConnRef.php.

Referenced by Wikimedia\Rdbms\DBConnRef\__call().

◆ estimateRowCount()

Wikimedia\Rdbms\DBConnRef::estimateRowCount ( $tables,
$var = ' *',
$conds = '',
$fname = __METHOD__,
$options = [],
$join_conds = [] )

Estimate the number of rows in dataset.

MySQL allows you to estimate the number of rows that would be returned by a SELECT query, using EXPLAIN SELECT. The estimate is provided using index cardinality statistics, and is notoriously inaccurate, especially when large numbers of rows have recently been added or deleted.

For DBMSs that don't support fast result size estimation, this function will actually perform the SELECT COUNT(*).

Takes the same arguments as IDatabase::select().

New callers should use newSelectQueryBuilder with SelectQueryBuilder::estimateRowCount instead, which is more readable and less error-prone.

Parameters
string | string[]$tablesTable name(s)
string$varColumn for which NULL values are not counted [default "*"]
array | string$condsFilters on the table
string$fnameFunction name for profiling
array$optionsOptions for select
array | string$join_condsJoin conditions
Returns
int Row count
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 347 of file DBConnRef.php.

◆ explicitTrxActive()

Wikimedia\Rdbms\DBConnRef::explicitTrxActive ( )

Check whether there is a transaction open at the specific request of a caller.

Explicit transactions are spawned by begin(), startAtomic(), and doAtomicSection(). Note that explicit transactions should not be confused with explicit transaction rounds.

Returns
bool
Since
1.28

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 134 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ factorConds()

Wikimedia\Rdbms\DBConnRef::factorConds ( $condsArray)

Given an array of condition arrays representing an OR list of AND lists, for example:

(A=1 AND B=2) OR (A=1 AND B=3)

produce an SQL expression in which the conditions are factored:

(A=1 AND (B=2 OR B=3))

We also use IN() to simplify further:

(A=1 AND (B IN (2,3))

More compactly, in boolean algebra notation, a sum of products, e.g. AB + AC is factored to produce A(B+C). Factoring proceeds recursively to reduce expressions with any number of variables, for example AEP + AEQ + AFP + AFQ = A(E(P+Q) + F(P+Q))

The algorithm is simple and will not necessarily find the shortest possible expression. For the best results, fields should be given in a consistent order, and the fields with values likely to be shared should be leftmost in the associative arrays.

Parameters
array$condsArrayAn array of associative arrays. The associative array keys represent field names, and the values represent the field values to compare against.
Returns
string SQL expression fragment

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 399 of file DBConnRef.php.

◆ fieldExists()

Wikimedia\Rdbms\DBConnRef::fieldExists ( $table,
$field,
$fname = __METHOD__ )

Determines whether a field exists in a table.

Parameters
string$tableTable name
string$fieldField to check on that table
string$fnameCalling function name (optional)
Returns
bool Whether $table has field $field
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IMaintainableDatabase.

Definition at line 367 of file DBConnRef.php.

◆ fieldInfo()

Wikimedia\Rdbms\DBConnRef::fieldInfo ( $table,
$field )

Get information about a field Returns false if the field doesn't exist.

Parameters
string$tableTable name
string$fieldField name
Returns
false|Field

Implements Wikimedia\Rdbms\IMaintainableDatabase.

Definition at line 868 of file DBConnRef.php.

◆ flushSession()

Wikimedia\Rdbms\DBConnRef::flushSession ( $fname = __METHOD__,
$flush = self::FLUSHING_ONE )

Release important session-level state (named lock, table locks) as post-rollback cleanup.

This should only be called by a load balancer or if the handle is not attached to one. Also, there must be no chance that a future caller will still be expecting some of the lost session state.

Connection and query errors will be suppressed and logged

Parameters
string$fnameCalling function name
string$flushFlush flag, set to a situationally valid IDatabase::FLUSHING_* constant to disable warnings about explicitly rolling back implicit transactions. This will silently break any ongoing explicit transaction. Only set the flush flag if you are sure that it is safe to ignore these warnings in your context.
Exceptions
DBErrorIf an error occurs, {
See also
query}
Since
1.38

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 680 of file DBConnRef.php.

◆ flushSnapshot()

Wikimedia\Rdbms\DBConnRef::flushSnapshot ( $fname = __METHOD__,
$flush = self::FLUSHING_ONE )

Commit any transaction but error out if writes or callbacks are pending.

This is intended for clearing out REPEATABLE-READ snapshots so that callers can see a new point-in-time of the database. This is useful when one of many transaction rounds finished and significant time will pass in the script's lifetime. It is also useful to call on a replica DB after waiting on replication to catch up to the primary DB.

Parameters
string$fnameCalling function name
string$flushFlush flag, set to situationally valid IDatabase::FLUSHING_* constant to disable warnings about explicitly committing implicit transactions, or calling commit when no transaction is in progress. This will trigger an exception if there is an ongoing explicit transaction. Only set the flush flag if you are sure that these warnings are not applicable, and no explicit transactions are open.
Exceptions
DBErrorIf an error occurs, {
See also
query}
Since
1.28
1.34 Added $flush parameter

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 684 of file DBConnRef.php.

◆ getDBname()

Wikimedia\Rdbms\DBConnRef::getDBname ( )

Get the current database name; null if there isn't one.

Returns
string|null

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 472 of file DBConnRef.php.

◆ getDomainChangeException()

Wikimedia\Rdbms\DBConnRef::getDomainChangeException ( )
protected

◆ getDomainID()

Wikimedia\Rdbms\DBConnRef::getDomainID ( )

Return the currently selected domain ID.

Null components (database/schema) might change once a connection is established

Returns
string

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 236 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call(), and Wikimedia\Rdbms\DatabaseDomain\getId().

◆ getFlag()

Wikimedia\Rdbms\DBConnRef::getFlag ( $flag)

Returns a boolean whether the flag $flag is set for this connection.

Parameters
int$flagOne of the class IDatabase::DBO_* constants
Returns
bool

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 228 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ getInfinity()

Wikimedia\Rdbms\DBConnRef::getInfinity ( )

Find out when 'infinity' is.

Most DBMSes support this. This is a special keyword for timestamps in PostgreSQL, and works with CHAR(14) as well because "i" sorts after all numbers.

Returns
string

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 754 of file DBConnRef.php.

◆ getLag()

Wikimedia\Rdbms\DBConnRef::getLag ( )

Get the amount of replication lag for this database server.

Callers should avoid using this method while a transaction is active

Returns
float|int|false Database replication lag in seconds or false on error
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 702 of file DBConnRef.php.

◆ getLBInfo()

Wikimedia\Rdbms\DBConnRef::getLBInfo ( $name = null)

Get properties passed down from the server info array of the load balancer.

Parameters
string | null$nameThe entry of the info array to get, or null to get the whole array
Returns
array|mixed|null

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 174 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ getPrimaryPos()

Wikimedia\Rdbms\DBConnRef::getPrimaryPos ( )

Get the position of this primary DB.

Returns
DBPrimaryPos|false False if this is not a primary DB
Exceptions
DBErrorIf an error occurs, {
See also
query}
Since
1.37

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 613 of file DBConnRef.php.

◆ getProperty()

Wikimedia\Rdbms\DBConnRef::getProperty ( $name)

Definition at line 232 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ getReferenceRole()

Wikimedia\Rdbms\DBConnRef::getReferenceRole ( )
Returns
int DB_PRIMARY when this requires the primary DB, otherwise DB_REPLICA
Since
1.33

Definition at line 110 of file DBConnRef.php.

◆ getReplicaPos()

Wikimedia\Rdbms\DBConnRef::getReplicaPos ( )

Get the replication position of this replica DB.

Returns
DBPrimaryPos|false False if this is not a replica DB
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 609 of file DBConnRef.php.

◆ getScopedLockAndFlush()

Wikimedia\Rdbms\DBConnRef::getScopedLockAndFlush ( $lockKey,
$fname,
$timeout )

Acquire a named lock, flush any transaction, and return an RAII style unlocker object.

Only call this from outer transaction scope and when only one DB will be affected. See https://www.mediawiki.org/wiki/Database_transactions for details.

This is suitable for transactions that need to be serialized using cooperative locks, where each transaction can see each others' changes. Any transaction is flushed to clear out stale REPEATABLE-READ snapshot data. Once the returned object falls out of PHP scope, the lock will be released unless a transaction is active. If one is active, then the lock will be released when it either commits or rolls back.

If the lock acquisition failed, then no transaction flush happens, and null is returned.

Parameters
string$lockKeyName of lock to release
string$fnameName of the calling method
int$timeoutAcquisition timeout in seconds
Returns
ScopedCallback|null
Exceptions
DBErrorIf an error occurs, {
See also
query}
Since
1.27

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 744 of file DBConnRef.php.

◆ getServer()

Wikimedia\Rdbms\DBConnRef::getServer ( )

Get the hostname or IP address of the server.

Returns
string|null

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 482 of file DBConnRef.php.

◆ getServerInfo()

Wikimedia\Rdbms\DBConnRef::getServerInfo ( )

Get a human-readable string describing the current software version.

Use getServerVersion() to get machine-friendly information.

Returns
string Version information from the database server

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 114 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ getServerName()

Wikimedia\Rdbms\DBConnRef::getServerName ( )

Get the readable name for the server.

Returns
string Readable server name, falling back to the hostname or IP address
Since
1.36

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 486 of file DBConnRef.php.

◆ getServerVersion()

Wikimedia\Rdbms\DBConnRef::getServerVersion ( )

A string describing the current software version, like from mysql_get_server_info()

Returns
string Version information from the database server.

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 279 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ getSessionLagStatus()

Wikimedia\Rdbms\DBConnRef::getSessionLagStatus ( )

Get the replica DB lag when the current transaction started or a general lag estimate if not transaction is active.

This is useful when transactions might use snapshot isolation (e.g. REPEATABLE-READ in innodb), so the "real" lag of that data is this lag plus transaction duration. If they don't, it is still safe to be pessimistic. In AUTOCOMMIT mode, this still gives an indication of the staleness of subsequent reads.

Returns
array ('lag': seconds or false on error, 'since': UNIX timestamp of BEGIN)
Exceptions
DBErrorIf an error occurs, {
See also
query}
Since
1.27

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 706 of file DBConnRef.php.

◆ getSoftwareLink()

Wikimedia\Rdbms\DBConnRef::getSoftwareLink ( )

Returns a wikitext style link to the DB's website (e.g.

"[https://www.mysql.com/ MySQL]")

Should at least contain plain text, if for some reason your database has no website.

Returns
string Wikitext of a link to the server software's web site

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 275 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ getTableAliases()

Wikimedia\Rdbms\DBConnRef::getTableAliases ( )

Return current table aliases.

Access: internal
only to be used inside rdbms library

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 778 of file DBConnRef.php.

◆ getTopologyBasedServerId()

Wikimedia\Rdbms\DBConnRef::getTopologyBasedServerId ( )

Get a non-recycled ID that uniquely identifies this server within the replication topology.

A replication topology defines which servers can originate changes to a given dataset and how those changes propagate among database servers. It is assumed that the server only participates in the replication of a single relevant dataset.

Returns
string|null 32, 64, or 128 bit integer ID; null if not applicable or unknown
Exceptions
DBQueryError
Since
1.37

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 118 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ getTopologyRole()

Wikimedia\Rdbms\DBConnRef::getTopologyRole ( )

Get the replication topology role of this server.

A replication topology defines which servers can originate changes to a given dataset and how those changes propagate among database servers. It is assumed that the server only participates in the replication of a single relevant dataset.

Returns
string One of the class ROLE_* constants
Exceptions
DBQueryError
Since
1.34

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 122 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ getType()

Wikimedia\Rdbms\DBConnRef::getType ( )

Get the RDBMS type of the server (e.g.

"mysql", "sqlite")

Returns
string

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 246 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call(), and Wikimedia\Rdbms\DBConnRef\normalizeServerIndex().

◆ implicitOrderby()

Wikimedia\Rdbms\DBConnRef::implicitOrderby ( )

Returns true if this database does an implicit order by when the column has an index For example: SELECT page_title FROM page LIMIT 1.

Returns
bool

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 184 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ indexExists()

Wikimedia\Rdbms\DBConnRef::indexExists ( $table,
$index,
$fname = __METHOD__ )

Determines whether an index exists.

Parameters
string$table
string$index
string$fname
Returns
bool|null
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IMaintainableDatabase.

Definition at line 371 of file DBConnRef.php.

◆ indexUnique()

Wikimedia\Rdbms\DBConnRef::indexUnique ( $table,
$index,
$fname = __METHOD__ )

Determines if a given index is unique.

Parameters
string$table
string$index
string$fnameCalling function name
Returns
bool

Implements Wikimedia\Rdbms\IMaintainableDatabase.

Definition at line 860 of file DBConnRef.php.

◆ insert()

Wikimedia\Rdbms\DBConnRef::insert ( $table,
$rows,
$fname = __METHOD__,
$options = [] )

Insert row(s) into a table, in the provided order.

Parameters
string$tableTable name
array | array[]$rowsRow(s) to insert, as either:
  • A string-keyed map of (column name => value) defining a new row. Values are treated as literals and quoted appropriately; null is interpreted as NULL.
  • An integer-keyed list of such string-keyed maps, defining a list of new rows. The keys in each map must be identical to each other and in the same order. The rows must not collide with each other.
string$fnameCalling function name (use METHOD) for logs/profiling
string | array$optionsCombination map/list where each string-keyed entry maps a non-boolean option to the option parameters and each integer-keyed value is the name of a boolean option. Supported options are:
  • IGNORE: Boolean: skip insertion of rows that would cause unique key conflicts. IDatabase::affectedRows() can be used to determine how many rows were inserted.
Returns
bool Return true if no exception was thrown (deprecated since 1.33)
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 379 of file DBConnRef.php.

◆ insertId()

Wikimedia\Rdbms\DBConnRef::insertId ( )

Get the inserted value of an auto-increment row.

This should only be called after an insert that used an auto-incremented value. If no such insert was previously done in the current database session, the return value is undefined.

Returns
int

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 259 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ insertSelect()

Wikimedia\Rdbms\DBConnRef::insertSelect ( $destTable,
$srcTable,
$varMap,
$conds,
$fname = __METHOD__,
$insertOptions = [],
$selectOptions = [],
$selectJoinConds = [] )

INSERT SELECT wrapper.

Warning
If the insert will use an auto-increment or sequence to determine the value of a column, this may break replication on databases using statement-based replication if the SELECT is not deterministically ordered.
Parameters
string$destTableThe table name to insert into
string | array$srcTableMay be either a table name, or an array of table names to include in a join.
array$varMapMust be an associative array of the form [ 'dest1' => 'source1', ... ]. Source items may be literals rather than field names, but strings should be quoted with IDatabase::addQuotes()
array$condsCondition array. See $conds in IDatabase::select() for the details of the format of condition arrays. May be "*" to copy the whole table.
string$fnameThe function name of the caller, from METHOD
array$insertOptionsOptions for the INSERT part of the query, see IDatabase::insert() for details. Also, one additional option is available: pass 'NO_AUTO_COLUMNS' to hint that the query does not use an auto-increment or sequence to determine any column values.
array$selectOptionsOptions for the SELECT part of the query, see IDatabase::select() for details.
array$selectJoinCondsJoin conditions for the SELECT part of the query, see IDatabase::select() for details.
Returns
bool Return true if no exception was thrown (deprecated since 1.33)
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 553 of file DBConnRef.php.

◆ isOpen()

Wikimedia\Rdbms\DBConnRef::isOpen ( )
Returns
bool Whether a connection to the database open

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 212 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ isReadOnly()

Wikimedia\Rdbms\DBConnRef::isReadOnly ( )
Returns
bool Whether this DB is read-only
Since
1.27

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 770 of file DBConnRef.php.

◆ lastDoneWrites()

Wikimedia\Rdbms\DBConnRef::lastDoneWrites ( )

Get the last time the connection may have been used for a write query.

Returns
int|float|false UNIX timestamp or false
Since
1.24

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 192 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ lastErrno()

Wikimedia\Rdbms\DBConnRef::lastErrno ( )

Get the RDBMS-specific error code from the last query statement.

Returns
int|string Error code (integer or hexadecimal depending on RDBMS type)

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 263 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ lastError()

Wikimedia\Rdbms\DBConnRef::lastError ( )

Get the RDBMS-specific error description from the last query statement.

Returns
string

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 267 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ lastQuery()

Wikimedia\Rdbms\DBConnRef::lastQuery ( )

Get the last query that sent on account of IDatabase::query()

Returns
string SQL text or empty string if there was no such query

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 188 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ limitResult()

Wikimedia\Rdbms\DBConnRef::limitResult ( $sql,
$limit,
$offset = false )

Construct a LIMIT query with optional offset.

The SQL should be adjusted so that only the first $limit rows are returned. If $offset is provided as well, then the first $offset rows should be discarded, and the next $limit rows should be returned. If the result of the query is not ordered, then the rows to be returned are theoretically arbitrary.

$sql is expected to be a SELECT, if that makes a difference.

Parameters
string$sqlSQL query we will append the limit too
int$limitThe SQL limit
int | false$offsetThe SQL offset (default false)
Returns
string
Since
1.34 in IDatabase, moved to ISQLPlatform in 1.39

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 336 of file DBConnRef.php.

◆ listTables()

Wikimedia\Rdbms\DBConnRef::listTables ( $prefix = null,
$fname = __METHOD__ )

List all tables on the database.

Parameters
string | null$prefixOnly show tables with this prefix, e.g. mw_
string$fnameCalling function name
Exceptions
DBError
Returns
array

Implements Wikimedia\Rdbms\IMaintainableDatabase.

Definition at line 864 of file DBConnRef.php.

◆ listViews()

Wikimedia\Rdbms\DBConnRef::listViews ( $prefix = null,
$fname = __METHOD__ )

Lists all the VIEWs in the database.

Parameters
string | null$prefixOnly show VIEWs with this prefix, eg. unit_test_
string$fnameName of calling function
Exceptions
RuntimeException
Returns
array

Implements Wikimedia\Rdbms\IMaintainableDatabase.

Definition at line 840 of file DBConnRef.php.

◆ lock()

Wikimedia\Rdbms\DBConnRef::lock ( $lockName,
$method,
$timeout = 5,
$flags = 0 )

Acquire a named lock.

Named locks are not related to transactions

Parameters
string$lockNameName of lock to acquire
string$methodName of the calling method
int$timeoutAcquisition timeout in seconds (0 means non-blocking)
int$flagsBit field of IDatabase::LOCK_* constants
Returns
bool|float|null Success (bool); acquisition time (float/null) if LOCK_TIMESTAMP
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 732 of file DBConnRef.php.

◆ lockForUpdate()

Wikimedia\Rdbms\DBConnRef::lockForUpdate ( $table,
$conds = '',
$fname = __METHOD__,
$options = [],
$join_conds = [] )

Lock all rows meeting the given conditions/options FOR UPDATE.

Parameters
string | string[]$tableTable name(s)
array | string$condsFilters on the table
string$fnameFunction name for profiling
array$optionsOptions for select ("FOR UPDATE" is added automatically)
array$join_condsJoin conditions
Returns
int Number of matching rows found (and locked)
Exceptions
DBErrorIf an error occurs, {
See also
query}
Since
1.32

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 359 of file DBConnRef.php.

◆ lockIsFree()

Wikimedia\Rdbms\DBConnRef::lockIsFree ( $lockName,
$method )

Check to see if a named lock is not locked by any thread (non-blocking)

Parameters
string$lockNameName of lock to poll
string$methodName of method calling us
Returns
bool
Exceptions
DBErrorIf an error occurs, {
See also
query}
Since
1.20

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 726 of file DBConnRef.php.

◆ makeList()

Wikimedia\Rdbms\DBConnRef::makeList ( array $a,
$mode = self::LIST_COMMA )

Makes an encoded list of strings from an array.

These can be used to make conjunctions or disjunctions on SQL condition strings derived from an array ({

See also
IDatabase::select} $conds documentation).

Example usage:

$sql = $db->makeList( [
'rev_page' => $id,
$db->makeList( [ 'rev_minor' => 1, 'rev_len < 500' ], $db::LIST_OR )
], $db::LIST_AND );

This would set $sql to "rev_page = '$id' AND (rev_minor = 1 OR rev_len < 500)"

Parameters
array$aContaining the data
int$modeIDatabase class constant:
  • IDatabase::LIST_COMMA: Comma separated, no field names
  • IDatabase::LIST_AND: ANDed WHERE clause (without the WHERE).
  • IDatabase::LIST_OR: ORed WHERE clause (without the WHERE)
  • IDatabase::LIST_SET: Comma separated with field names, like a SET clause
  • IDatabase::LIST_NAMES: Comma separated field names
Exceptions
DBErrorIf an error occurs, {
See also
IDatabase::query}
Returns
string

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 391 of file DBConnRef.php.

◆ makeWhereFrom2d()

Wikimedia\Rdbms\DBConnRef::makeWhereFrom2d ( $data,
$baseKey,
$subKey )

Build a partial where clause from a 2-d array such as used for LinkBatch.

The keys on each level may be either integers or strings, however it's assumed that $baseKey is probably an integer-typed column (i.e. integer keys are unquoted in the SQL) and $subKey is string-typed (i.e. integer keys are quoted as strings in the SQL).

Todo
Does this actually belong in the library? It seems overly MW-specific.
Parameters
array$dataOrganized as 2-d [ baseKeyVal => [ subKeyVal => [ignored], ... ], ... ]
string$baseKeyField name to match the base-level keys to (eg 'pl_namespace')
string$subKeyField name to match the sub-level keys to (eg 'pl_title')
Returns
string|false SQL fragment, or false if no items in array

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 395 of file DBConnRef.php.

◆ namedLocksEnqueue()

Wikimedia\Rdbms\DBConnRef::namedLocksEnqueue ( )

Check to see if a named lock used by lock() use blocking queues.

Returns
bool
Since
1.26

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 750 of file DBConnRef.php.

◆ newSelectQueryBuilder()

Wikimedia\Rdbms\DBConnRef::newSelectQueryBuilder ( )

Create an empty SelectQueryBuilder which can be used to run queries against this connection.

Note
A new query builder must be created per query. Query builders should not be reused since this uses a fluent interface and the state of the builder changes during the query which may cause unexpected results.
Returns
SelectQueryBuilder

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 305 of file DBConnRef.php.

◆ nextSequenceValue()

Wikimedia\Rdbms\DBConnRef::nextSequenceValue ( $seqName)

Deprecated method, calls should be removed.

This was formerly used for PostgreSQL to handle self::insertId() auto-incrementing fields. It is no longer necessary since DatabasePostgres::insertId() has been reimplemented using lastval()

Implementations should return null if inserting NULL into an auto-incrementing field works, otherwise it should return an instance of NextSequenceValue and filter it on calls to relevant methods.

Deprecated
since 1.30, no longer needed
Parameters
string$seqName
Returns
null|NextSequenceValue

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 519 of file DBConnRef.php.

◆ normalizeServerIndex()

Wikimedia\Rdbms\DBConnRef::normalizeServerIndex ( $i)
protected
Parameters
int$iSpecific or virtual (DB_PRIMARY/DB_REPLICA) server index
Returns
int|mixed

Definition at line 916 of file DBConnRef.php.

Referenced by Wikimedia\Rdbms\DBConnRef\getType().

◆ onAtomicSectionCancel()

Wikimedia\Rdbms\DBConnRef::onAtomicSectionCancel ( callable $callback,
$fname = __METHOD__ )

Run a callback when the atomic section is cancelled.

The callback is run just after the current atomic section, any outer atomic section, or the whole transaction is rolled back.

An error is thrown if no atomic section is pending. The atomic section need not have been created with the ATOMIC_CANCELABLE flag.

Queries in the function may be running in the context of an outer transaction or may be running in AUTOCOMMIT mode. The callback should use atomic sections if necessary.

Note
do not assume that other IDatabase instances will be AUTOCOMMIT mode

The callback takes the following arguments:

  • IDatabase::TRIGGER_CANCEL or IDatabase::TRIGGER_ROLLBACK
  • This IDatabase instance
Parameters
callable$callback
string$fnameCaller name
Since
1.34

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 636 of file DBConnRef.php.

◆ onTransactionCommitOrIdle()

Wikimedia\Rdbms\DBConnRef::onTransactionCommitOrIdle ( callable $callback,
$fname = __METHOD__ )

Run a callback when the current transaction commits or now if there is none.

If there is a transaction and it is rolled back, then the callback is cancelled.

When transaction round mode (DBO_TRX) is set, the callback will run at the end of the round, just after all peer transactions COMMIT. If the transaction round is rolled back, then the callback is cancelled.

This IDatabase instance will start off in auto-commit mode when the callback starts. The use of other IDatabase handles from the callback should be avoided unless they are known to be in auto-commit mode. Callbacks that create transactions via begin() or startAtomic() must have matching calls to commit()/endAtomic().

Use this method only for the following purposes:

  • (a) RDBMS updates, prone to lock timeouts/deadlocks, that do not require atomicity with respect to the updates in the current transaction (if any)
  • (b) Purges to lightweight cache services due to RDBMS updates
  • (c) Updates to secondary DBs/stores that must only commit once the updates in the current transaction (if any) are committed (e.g. insert user account row to DB1, then, initialize corresponding LDAP account)

The callback takes the following arguments:

  • How the transaction ended (IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_IDLE)
  • This IDatabase instance (since 1.32)

Callbacks will execute in the order they were enqueued.

Parameters
callable$callback
string$fnameCaller name
Exceptions
DBErrorIf an error occurs, {
See also
query}
Exceptions
ExceptionIf the callback runs immediately and an error occurs in it
Since
1.32

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 626 of file DBConnRef.php.

◆ onTransactionPreCommitOrIdle()

Wikimedia\Rdbms\DBConnRef::onTransactionPreCommitOrIdle ( callable $callback,
$fname = __METHOD__ )

Run a callback before the current transaction commits or now if there is none.

If there is a transaction and it is rolled back, then the callback is cancelled.

When transaction round mode (DBO_TRX) is set, the callback will run at the end of the round, just after all peer transactions COMMIT. If the transaction round is rolled back, then the callback is cancelled.

If there is no current transaction, one will be created to wrap the callback. Callbacks cannot use begin()/commit() to manage transactions. The use of other IDatabase handles from the callback should be avoided.

Use this method only for the following purposes:

  • a) RDBMS updates, prone to lock timeouts/deadlocks, that require atomicity with respect to the updates in the current transaction (if any)
  • b) Purges to lightweight cache services due to RDBMS updates

The callback takes the one argument:

  • This IDatabase instance (since 1.32)

Callbacks will execute in the order they were enqueued.

Parameters
callable$callback
string$fnameCaller name
Exceptions
DBErrorIf an error occurs, {
See also
query}
Exceptions
ExceptionIf the callback runs immediately and an error occurs in it
Since
1.22

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 631 of file DBConnRef.php.

◆ onTransactionResolution()

Wikimedia\Rdbms\DBConnRef::onTransactionResolution ( callable $callback,
$fname = __METHOD__ )

Run a callback when the current transaction commits or rolls back.

An error is thrown if no transaction is pending.

When transaction round mode (DBO_TRX) is set, the callback will run at the end of the round, just after all peer transactions COMMIT/ROLLBACK.

This IDatabase instance will start off in auto-commit mode when the callback starts. The use of other IDatabase handles from the callback should be avoided unless they are known to be in auto-commit mode. Callbacks that create transactions via begin() or startAtomic() must have matching calls to commit()/endAtomic().

Use this method only for the following purposes:

  • (a) Release of cooperative locks on resources
  • (b) Cancellation of in-process deferred tasks

The callback takes the following arguments:

  • How the current atomic section (if any) or overall transaction (otherwise) ended (IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_ROLLBACK)
  • This IDatabase instance (since 1.32)

Callbacks will execute in the order they were enqueued.

Note
Use onAtomicSectionCancel() to take action as soon as an atomic section is cancelled
Parameters
callable$callback
string$fnameCaller name
Exceptions
DBErrorIf an error occurs, {
See also
query}
Exceptions
ExceptionIf the callback runs immediately and an error occurs in it
Since
1.28

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 621 of file DBConnRef.php.

◆ pendingWriteCallers()

Wikimedia\Rdbms\DBConnRef::pendingWriteCallers ( )

Get the list of method names that did write queries for this transaction.

Returns
array
Since
1.27

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 208 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ pendingWriteQueryDuration()

Wikimedia\Rdbms\DBConnRef::pendingWriteQueryDuration ( $type = self::ESTIMATE_TOTAL)

Get the time spend running write queries for this transaction.

High values could be due to scanning, updates, locking, and such.

Parameters
string$typeIDatabase::ESTIMATE_* constant [default: ESTIMATE_ALL]
Returns
float|false Returns false if not transaction is active
Since
1.26

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 204 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ ping()

Wikimedia\Rdbms\DBConnRef::ping ( & $rtt = null)

Ping the server and try to reconnect if it there is no connection.

Parameters
float | null&$rttValue to store the estimated RTT [optional]
Returns
bool Success or failure

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 696 of file DBConnRef.php.

◆ primaryPosWait()

Wikimedia\Rdbms\DBConnRef::primaryPosWait ( DBPrimaryPos $pos,
$timeout )

Wait for the replica DB to catch up to a given primary DB position.

Note that this does not start any new transactions. If any existing transaction is flushed, and this is called, then queries will reflect the point the DB was synced up to (on success) without interference from REPEATABLE-READ snapshots.

Parameters
DBPrimaryPos$pos
int$timeoutThe maximum number of seconds to wait for synchronisation
Returns
int|null Zero if the replica DB was past that position already, greater than zero if we waited for some period of time, less than zero if it timed out, and null on error
Exceptions
DBErrorIf an error occurs, {
See also
query}
Since
1.37

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 605 of file DBConnRef.php.

◆ query()

Wikimedia\Rdbms\DBConnRef::query ( $sql,
$fname = __METHOD__,
$flags = 0 )

Run an SQL query statement and return the result.

If a connection loss is detected, then an attempt to reconnect will be made. For queries that involve no larger transactions or locks, they will be re-issued for convenience, provided the connection was re-established.

In new code, the query wrappers select(), insert(), update(), delete(), etc. should be used where possible, since they give much better DBMS independence and automatically quote or validate user input in a variety of contexts. This function is generally only useful for queries which are explicitly DBMS-dependent and are unsupported by the query wrappers, such as CREATE TABLE.

However, the query wrappers themselves should call this function.

Parameters
string$sqlSingle-statement SQL query
string$fnameCaller name; used for profiling/SHOW PROCESSLIST comments
int$flagsBit field of IDatabase::QUERY_* constants.
Returns
bool|IResultWrapper True for a successful write query, IResultWrapper object for a successful read query, or false on failure if QUERY_SILENCE_ERRORS is set.
Exceptions
DBQueryErrorIf the query is issued, fails, and QUERY_SILENCE_ERRORS is not set.
DBExpectedErrorIf the query is not, and cannot, be issued yet (non-DBQueryError)
DBErrorIf the query is inherently not allowed (non-DBExpectedError)

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 288 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call(), and Wikimedia\Rdbms\ILoadBalancer\DB_PRIMARY.

◆ queryMulti()

Wikimedia\Rdbms\DBConnRef::queryMulti ( array $sqls,
string $fname = __METHOD__,
int $flags = 0,
?string $summarySql = null )

Run a batch of SQL query statements and return the results.

See also
IDatabase::query()
Parameters
string[]$sqlsMap of (statement ID => SQL statement)
string$fnameName of the calling function
int$flagsBit field of IDatabase::QUERY_* constants
string | null$summarySqlVirtual SQL for profiling (e.g. "UPSERT INTO TABLE 'x'")
Returns
array<string,QueryStatus> Ordered map of (statement ID => QueryStatus)
Since
1.39

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 296 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call(), and Wikimedia\Rdbms\ILoadBalancer\DB_PRIMARY.

◆ replace()

Wikimedia\Rdbms\DBConnRef::replace ( $table,
$uniqueKeys,
$rows,
$fname = __METHOD__ )

Insert row(s) into a table, in the provided order, while deleting conflicting rows.

Conflicts are determined by the provided unique indexes. Note that it is possible for the provided rows to conflict even among themselves; it is preferable for the caller to de-duplicate such input beforehand.

Note some important implications of the deletion semantics:

  • If the table has an AUTOINCREMENT column and $rows omit that column, then any conflicting existing rows will be replaced with newer having higher values for that column, even if nothing else changed.
  • There might be worse contention than upsert() due to the use of gap-locking. This does not apply to RDBMS types that use predicate locking nor those that just lock the whole table or databases anyway.
Parameters
string$tableThe table name
string | string[] | string[][]$uniqueKeysColumn name or non-empty list of column name lists that define all applicable unique keys on the table. There must only be one such key. Each unique key on the table is "applicable" unless either:
  • It involves an AUTOINCREMENT column for which no values are assigned in $rows
  • It involves a UUID column for which newly generated UUIDs are assigned in $rows
array | array[]$rowsRow(s) to insert, in the form of either:
  • A string-keyed map of (column name => value) defining a new row. Values are treated as literals and quoted appropriately; null is interpreted as NULL. Columns belonging to a key in $uniqueKeys must be defined here and non-null.
  • An integer-keyed list of such string-keyed maps, defining a list of new rows. The keys in each map must be identical to each other and in the same order. The rows must not collide with each other.
string$fnameCalling function name (use METHOD) for logs/profiling
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 525 of file DBConnRef.php.

◆ restoreFlags()

Wikimedia\Rdbms\DBConnRef::restoreFlags ( $state = self::RESTORE_PRIOR)

Restore the flags to their prior state before the last setFlag/clearFlag call.

Parameters
string$stateIDatabase::RESTORE_* constant. [default: RESTORE_PRIOR]
Since
1.28

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 224 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ rollback()

Wikimedia\Rdbms\DBConnRef::rollback ( $fname = __METHOD__,
$flush = self::FLUSHING_ONE )

Rollback a transaction previously started using begin()

Only call this from code with outer transaction scope. See https://www.mediawiki.org/wiki/Database_transactions for details. Nesting of transactions is not supported. If a serious unexpected error occurs, throwing an Exception is preferable, using a pre-installed error handler to trigger rollback (in any case, failure to issue COMMIT will cause rollback server-side).

Query, connection, and onTransaction* callback errors will be suppressed and logged.

Parameters
string$fnameCalling function name
string$flushFlush flag, set to a situationally valid IDatabase::FLUSHING_* constant to disable warnings about explicitly rolling back implicit transactions. This will silently break any ongoing explicit transaction. Only set the flush flag if you are sure that it is safe to ignore these warnings in your context.
Exceptions
DBErrorIf an error occurs, {
See also
query}
Since
1.23 Added $flush parameter

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 676 of file DBConnRef.php.

◆ select()

Wikimedia\Rdbms\DBConnRef::select ( $table,
$vars,
$conds = '',
$fname = __METHOD__,
$options = [],
$join_conds = [] )

Execute a SELECT query constructed using the various parameters provided.

New callers should use newSelectQueryBuilder with SelectQueryBuilder::fetchResultSet instead, which is more readable and less error-prone.

Parameters
string | array$tableTable name(s)

May be either an array of table names, or a single string holding a table name. If an array is given, table aliases can be specified, for example:

[ 'a' => 'user' ]

This includes the user table in the query, with the alias "a" available for use in field names (e.g. a.user_name).

A derived table, defined by the result of selectSQLText(), requires an alias key and a Subquery instance value which wraps the SQL query, for example:

[ 'c' => new Subquery( 'SELECT ...' ) ]

Joins using parentheses for grouping (since MediaWiki 1.31) may be constructed using nested arrays. For example,

[ 'tableA', 'nestedB' => [ 'tableB', 'b2' => 'tableB2' ] ]

along with $join_conds like

[ 'b2' => [ 'JOIN', 'b_id = b2_id' ], 'nestedB' => [ 'LEFT JOIN', 'b_a = a_id' ] ]

will produce SQL something like

FROM tableA LEFT JOIN (tableB JOIN tableB2 AS b2 ON (b_id = b2_id)) ON (b_a = a_id)

All of the table names given here are automatically run through Database::tableName(), which causes the table prefix (if any) to be added, and various other table name mappings to be performed.

Do not use untrusted user input as a table name. Alias names should not have characters outside of the Basic multilingual plane.

Parameters
string | array$varsField name(s)

May be either a field name or an array of field names. The field names can be complete fragments of SQL, for direct inclusion into the SELECT query. If an array is given, field aliases can be specified, for example:

[ 'maxrev' => 'MAX(rev_id)' ]

This includes an expression with the alias "maxrev" in the query.

If an expression is given, care must be taken to ensure that it is DBMS-independent.

Untrusted user input must not be passed to this parameter.

Parameters
string | array$conds

May be either a string containing a single condition, or an array of conditions. If an array is given, the conditions constructed from each element are combined with AND.

Array elements may take one of two forms:

  • Elements with a numeric key are interpreted as raw SQL fragments.
  • Elements with a string key are interpreted as equality conditions, where the key is the field name.
    • If the value of such an array element is a scalar (such as a string), it will be treated as data and thus quoted appropriately. If it is null, an IS NULL clause will be added.
    • If the value is an array, an IN (...) clause will be constructed from its non-null elements, and an IS NULL clause will be added if null is present, such that the field may match any of the elements in the array. The non-null elements will be quoted.

Note that expressions are often DBMS-dependent in their syntax. DBMS-independent wrappers are provided for constructing several types of expression commonly used in condition queries. See:

  • IDatabase::buildLike()
  • IDatabase::conditional()

Untrusted user input is safe in the values of string keys, however untrusted input must not be used in the array key names or in the values of numeric keys. Escaping of untrusted input used in values of numeric keys should be done via IDatabase::addQuotes()

Use an empty array, string, or IDatabase::ALL_ROWS to select all rows.

You can put simple join conditions here, but this is strongly discouraged. Instead of

// $conds...
'rev_actor = actor_id',

use (see below for $join_conds):

// $join_conds...
'actor' => [ 'JOIN', 'rev_actor = actor_id' ],
Parameters
string$fnameCaller function name
string | array$optionsQuery options

Optional: Array of query options. Boolean options are specified by including them in the array as a string value with a numeric key, for example:

[ 'FOR UPDATE' ]

The supported options are:

  • OFFSET: Skip this many rows at the start of the result set. OFFSET with LIMIT can theoretically be used for paging through a result set, but this is discouraged for performance reasons.
  • LIMIT: Integer: return at most this many rows. The rows are sorted and then the first rows are taken until the limit is reached. LIMIT is applied to a result set after OFFSET.
  • LOCK IN SHARE MODE: Boolean: lock the returned rows so that they can't be changed until the next COMMIT. Cannot be used with aggregate functions (COUNT, MAX, etc., but also DISTINCT).
  • FOR UPDATE: Boolean: lock the returned rows so that they can't be changed nor read with LOCK IN SHARE MODE until the next COMMIT. Cannot be used with aggregate functions (COUNT, MAX, etc., but also DISTINCT).
  • DISTINCT: Boolean: return only unique result rows.
  • GROUP BY: May be either an SQL fragment string naming a field or expression to group by, or an array of such SQL fragments.
  • HAVING: May be either an string containing a HAVING clause or an array of conditions building the HAVING clause. If an array is given, the conditions constructed from each element are combined with AND.
  • ORDER BY: May be either an SQL fragment giving a field name or expression to order by, or an array of such SQL fragments.
  • USE INDEX: This may be either a string giving the index name to use for the query, or an array. If it is an associative array, each key gives the table name (or alias), each value gives the index name to use for that table. All strings are SQL fragments and so should be validated by the caller.
  • IGNORE INDEX: This may be either be a string giving an index name to ignore for the query, or an array. If it is an associative array, each key gives the table name (or alias), each value gives the index name to ignore for that table. All strings are SQL fragments and so should be validated by the caller.
  • EXPLAIN: In MySQL, this causes an EXPLAIN SELECT query to be run, instead of SELECT.
  • MAX_EXECUTION_TIME: (only in MySQL/MariaDB) maximum allowed time to run the query in milliseconds (if database supports it).

And also the following boolean MySQL extensions, see the MySQL manual for documentation:

  • STRAIGHT_JOIN
  • SQL_BIG_RESULT
  • SQL_BUFFER_RESULT
  • SQL_SMALL_RESULT
  • SQL_CALC_FOUND_ROWS
Parameters
string | array$join_condsJoin conditions

Optional associative array of table-specific join conditions. Simple conditions can also be specified in the regular $conds, but this is strongly discouraged in favor of the more explicit syntax here.

The key of the array contains the table name or alias. The value is an array with two elements, numbered 0 and 1. The first gives the type of join, the second is the same as the $conds parameter. Thus it can be an SQL fragment, or an array where the string keys are equality and the numeric keys are SQL fragments all AND'd together. For example:

[ 'page' => [ 'LEFT JOIN', 'page_latest=rev_id' ] ]

Returns
IResultWrapper Resulting rows
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 322 of file DBConnRef.php.

◆ selectDB()

Wikimedia\Rdbms\DBConnRef::selectDB ( $db)

Change the current database.

This should only be called by a load balancer or if the handle is not attached to one

Parameters
string$db
Returns
bool True unless an exception was thrown
Exceptions
DBConnectionErrorIf databasesAreIndependent() is true and connection change fails
DBErrorOn query error or if database changes are disallowed
Deprecated
Since 1.32 Use selectDomain() instead

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 460 of file DBConnRef.php.

◆ selectDomain()

Wikimedia\Rdbms\DBConnRef::selectDomain ( $domain)

Set the current domain (database, schema, and table prefix)

This will throw an error for some database types if the database is unspecified

This should only be called by a load balancer or if the handle is not attached to one

Parameters
string | DatabaseDomain$domain
Exceptions
DBConnectionErrorIf databasesAreIndependent() is true and connection change fails
DBErrorOn query error, if domain changes are disallowed, or the domain is invalid
Since
1.32

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 466 of file DBConnRef.php.

◆ selectField()

Wikimedia\Rdbms\DBConnRef::selectField ( $table,
$var,
$cond = '',
$fname = __METHOD__,
$options = [],
$join_conds = [] )

A SELECT wrapper which returns a single field from a single result row.

If no result rows are returned from the query, false is returned.

New callers should use newSelectQueryBuilder with SelectQueryBuilder::fetchField instead, which is more readable and less error-prone.

Parameters
string | array$tableTable name. {
See also
select} for details.
Parameters
string | array$varThe field name to select. This must be a valid SQL fragment: do not use unvalidated user input. Can be an array, but must contain exactly 1 element then. {
See also
select} for details.
Parameters
string | array$condThe condition array. {
See also
select} for details.
Parameters
string$fnameThe function name of the caller.
string | array$optionsThe query options. {
See also
select} for details.
Parameters
string | array$join_condsThe query join conditions. {
See also
select} for details.
Returns
mixed|false The value from the field, or false if nothing was found
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 310 of file DBConnRef.php.

◆ selectFieldValues()

Wikimedia\Rdbms\DBConnRef::selectFieldValues ( $table,
$var,
$cond = '',
$fname = __METHOD__,
$options = [],
$join_conds = [] )

A SELECT wrapper which returns a list of single field values from result rows.

If no result rows are returned from the query, an empty array is returned.

New callers should use newSelectQueryBuilder with SelectQueryBuilder::fetchFieldValues instead, which is more readable and less error-prone.

Parameters
string | array$tableTable name. {
See also
select} for details.
Parameters
string$varThe field name to select. This must be a valid SQL fragment: do not use unvalidated user input.
string | array$condThe condition array. {
See also
select} for details.
Parameters
string$fnameThe function name of the caller.
string | array$optionsThe query options. {
See also
select} for details.
Parameters
string | array$join_condsThe query join conditions. {
See also
select} for details.
Returns
array The values from the field in the order they were returned from the DB
Exceptions
DBErrorIf an error occurs, {
See also
query}
Since
1.25

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 316 of file DBConnRef.php.

◆ selectRow()

Wikimedia\Rdbms\DBConnRef::selectRow ( $table,
$vars,
$conds,
$fname = __METHOD__,
$options = [],
$join_conds = [] )

Wrapper to IDatabase::select() that only fetches one row (via LIMIT)

If the query returns no rows, false is returned.

This method is convenient for fetching a row based on a unique key condition.

New callers should use newSelectQueryBuilder with SelectQueryBuilder::fetchRow instead, which is more readable and less error-prone.

Parameters
string | array$tableTable name
string | array$varsField names
string | array$condsConditions
string$fnameCaller function name
string | array$optionsQuery options
array | string$join_condsJoin conditions
Returns
stdClass|bool
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 340 of file DBConnRef.php.

◆ selectRowCount()

Wikimedia\Rdbms\DBConnRef::selectRowCount ( $tables,
$var = ' *',
$conds = '',
$fname = __METHOD__,
$options = [],
$join_conds = [] )

Get the number of rows in dataset.

This is useful when trying to do COUNT(*) but with a LIMIT for performance.

Takes the same arguments as IDatabase::select().

New callers should use newSelectQueryBuilder with SelectQueryBuilder::fetchRowCount instead, which is more readable and less error-prone.

Since
1.27 Added $join_conds parameter
Parameters
string | string[]$tablesTable name(s)
string$varColumn for which NULL values are not counted [default "*"]
array | string$condsFilters on the table
string$fnameFunction name for profiling
array$optionsOptions for select
array$join_condsJoin conditions (since 1.27)
Returns
int Row count
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 353 of file DBConnRef.php.

◆ selectSQLText()

Wikimedia\Rdbms\DBConnRef::selectSQLText ( $table,
$vars,
$conds = '',
$fname = __METHOD__,
$options = [],
$join_conds = [] )

Take the same arguments as IDatabase::select() and return the SQL it would use.

This can be useful for making UNION queries, where the SQL text of each query is needed. In general, however, callers outside of Database classes should just use select().

See also
IDatabase::select()
Parameters
string | array$tableTable name(s)
string | array$varsField names
string | array$condsConditions
string$fnameCaller function name
string | array$optionsQuery options
string | array$join_condsJoin conditions
Returns
string SQL query string

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 329 of file DBConnRef.php.

◆ serverIsReadOnly()

Wikimedia\Rdbms\DBConnRef::serverIsReadOnly ( )
Returns
bool Whether the DB is marked as read-only server-side
Exceptions
DBErrorIf an error occurs, {
See also
query}
Since
1.28

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 617 of file DBConnRef.php.

◆ setBigSelects()

Wikimedia\Rdbms\DBConnRef::setBigSelects ( $value = true)

Allow or deny "big selects" for this session only.

This is done by setting the sql_big_selects session variable.

This is a MySQL-specific feature.

Parameters
bool | string$valueTrue for allow, false for deny, or "default" to restore the initial value

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 766 of file DBConnRef.php.

◆ setFlag()

Wikimedia\Rdbms\DBConnRef::setFlag ( $flag,
$remember = self::REMEMBER_NOTHING )

Set a flag for this connection.

Parameters
int$flagOne of (IDatabase::DBO_DEBUG, IDatabase::DBO_TRX)
string$rememberIDatabase::REMEMBER_* constant [default: REMEMBER_NOTHING]

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 216 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ setIndexAliases()

Wikimedia\Rdbms\DBConnRef::setIndexAliases ( array $aliases)

Convert certain index names to alternative names before querying the DB.

Note that this applies to indexes regardless of the table they belong to.

This can be employed when an index was renamed X => Y in code, but the new Y-named indexes were not yet built on all DBs. After all the Y-named ones are added by the DBA, the aliases can be removed, and then the old X-named indexes dropped.

Parameters
string[]$aliases
Since
1.31 in IDatabase, moved to ISQLPlatform in 1.39

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 782 of file DBConnRef.php.

◆ setLBInfo()

Wikimedia\Rdbms\DBConnRef::setLBInfo ( $nameOrArray,
$value = null )

Set the entire array or a particular key of the managing load balancer info array.

Keys matching the IDatabase::LB_* constants are also used internally by subclasses

Parameters
array | string$nameOrArrayThe new array or the name of a key to set
array | mixed | null$valueIf $nameOrArray is a string, the new key value (null to unset)

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 178 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\getDomainChangeException().

◆ setSchemaVars()

Wikimedia\Rdbms\DBConnRef::setSchemaVars ( $vars)

Set schema variables to be used when streaming commands from SQL files or stdin.

Variables appear as SQL comments and are substituted by their corresponding values

Parameters
array | null$varsMap of (variable => value) or null to use the defaults

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 722 of file DBConnRef.php.

◆ setSessionOptions()

Wikimedia\Rdbms\DBConnRef::setSessionOptions ( array $options)

Override database's default behavior.

$options include: 'connTimeout' : Set the connection timeout value in seconds. May be useful for very long batch queries such as full-wiki dumps, where a single query reads out over hours or days.

Parameters
array$options
Returns
void
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 718 of file DBConnRef.php.

◆ setTableAliases()

Wikimedia\Rdbms\DBConnRef::setTableAliases ( array $aliases)

Make certain table names use their own database, schema, and table prefix when passed into SQL queries pre-escaped and without a qualified database name.

For example, "user" can be converted to "myschema.mydbname.user" for convenience. Appearances like user, somedb.user, somedb.someschema.user will used literally.

Calling this twice will completely clear any old table aliases. Also, note that callers are responsible for making sure the schemas and databases actually exist.

Parameters
array[]$aliasesMap of (table => (dbname, schema, prefix) map)
Since
1.28 in IDatabase, moved to ISQLPlatform in 1.39

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 774 of file DBConnRef.php.

◆ setTransactionListener()

Wikimedia\Rdbms\DBConnRef::setTransactionListener ( $name,
callable $callback = null )

Run a callback after each time any transaction commits or rolls back.

The callback takes two arguments:

  • IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_ROLLBACK
  • This IDatabase object Callbacks must commit any transactions that they begin.

Registering a callback here will not affect writesOrCallbacks() pending.

Since callbacks from this or onTransactionCommitOrIdle() can start and end transactions, a single call to IDatabase::commit might trigger multiple runs of the listener callbacks.

Parameters
string$nameCallback name
callable | null$callbackUse null to unset a listener
Since
1.28

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 640 of file DBConnRef.php.

◆ sourceFile()

Wikimedia\Rdbms\DBConnRef::sourceFile ( $filename,
callable $lineCallback = null,
callable $resultCallback = null,
$fname = false,
callable $inputCallback = null )

Read and execute SQL commands from a file.

Returns true on success, error string or exception on failure (depending on object's error ignore settings).

Parameters
string$filenameFile name to open
callable | null$lineCallbackOptional function called before reading each line
callable | null$resultCallbackOptional function called for each MySQL result
string | false$fnameCalling function name or false if name should be generated dynamically using $filename
callable | null$inputCallbackOptional function called for each complete line sent
Returns
bool|string
Exceptions
Exception

Implements Wikimedia\Rdbms\IMaintainableDatabase.

Definition at line 798 of file DBConnRef.php.

◆ sourceStream()

Wikimedia\Rdbms\DBConnRef::sourceStream ( $fp,
callable $lineCallback = null,
callable $resultCallback = null,
$fname = __METHOD__,
callable $inputCallback = null )

Read and execute commands from an open file handle.

Returns true on success, error string or exception on failure (depending on object's error ignore settings).

Parameters
resource$fpFile handle
callable | null$lineCallbackOptional function called before reading each query
callable | null$resultCallbackOptional function called for each MySQL result
string$fnameCalling function name
callable | null$inputCallbackOptional function called for each complete query sent
Returns
bool|string

Implements Wikimedia\Rdbms\IMaintainableDatabase.

Definition at line 810 of file DBConnRef.php.

◆ startAtomic()

Wikimedia\Rdbms\DBConnRef::startAtomic ( $fname = __METHOD__,
$cancelable = IDatabase::ATOMIC_NOT_CANCELABLE )

Begin an atomic section of SQL statements.

Start an implicit transaction if no transaction is already active, set a savepoint (if $cancelable is ATOMIC_CANCELABLE), and track the given section name to enforce that the transaction is not committed prematurely. The end of the section must be signified exactly once, either by endAtomic() or cancelAtomic(). Sections can have have layers of inner sections (sub-sections), but all sections must be ended in order of innermost to outermost. Transactions cannot be started or committed until all atomic sections are closed.

ATOMIC_CANCELABLE is useful when the caller needs to handle specific failure cases by discarding the section's writes. This should not be used for failures when:

  • upsert() could easily be used instead
  • insert() with IGNORE could easily be used instead
  • select() with FOR UPDATE could be checked before issuing writes instead
  • The failure is from code that runs after the first write but doesn't need to
  • The failures are from contention solvable via onTransactionPreCommitOrIdle()
  • The failures are deadlocks; the RDBMs usually discard the whole transaction
Note
callers must use additional measures for situations involving two or more (peer) transactions (e.g. updating two database servers at once). The transaction and savepoint logic of this method only applies to this specific IDatabase instance.

Example usage:

// Start a transaction if there isn't one already
$dbw->startAtomic( __METHOD__ );
// Serialize these thread table updates
$dbw->select( 'thread', '1', [ 'td_id' => $tid ], __METHOD__, 'FOR UPDATE' );
// Add a new comment for the thread
$dbw->insert( 'comment', $row, __METHOD__ );
$cid = $db->insertId();
// Update thread reference to last comment
$dbw->update( 'thread', [ 'td_latest' => $cid ], [ 'td_id' => $tid ], __METHOD__ );
// Demark the end of this conceptual unit of updates
$dbw->endAtomic( __METHOD__ );

Example usage (atomic changes that might have to be discarded):

// Start a transaction if there isn't one already
$sectionId = $dbw->startAtomic( __METHOD__, $dbw::ATOMIC_CANCELABLE );
// Create new record metadata row
$dbw->insert( 'records', $row, __METHOD__ );
// Figure out where to store the data based on the new row's ID
$path = $recordDirectory . '/' . $dbw->insertId();
// Write the record data to the storage system
$status = $fileBackend->create( [ 'dst' => $path, 'content' => $data ] );
if ( $status->isOK() ) {
// Try to cleanup files orphaned by transaction rollback
$dbw->onTransactionResolution(
function ( $type ) use ( $fileBackend, $path ) {
if ( $type === IDatabase::TRIGGER_ROLLBACK ) {
$fileBackend->delete( [ 'src' => $path ] );
}
},
__METHOD__
);
// Demark the end of this conceptual unit of updates
$dbw->endAtomic( __METHOD__ );
} else {
// Discard these writes from the transaction (preserving prior writes)
$dbw->cancelAtomic( __METHOD__, $sectionId );
}
Since
1.23
Parameters
string$fname
string$cancelablePass self::ATOMIC_CANCELABLE to use a savepoint and enable self::cancelAtomic() for this section.
Returns
AtomicSectionIdentifier section ID token
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 644 of file DBConnRef.php.

◆ streamStatementEnd()

Wikimedia\Rdbms\DBConnRef::streamStatementEnd ( & $sql,
& $newLine )

Called by sourceStream() to check if we've reached a statement end.

Parameters
string&$sqlSQL assembled so far
string&$newLineNew line about to be added to $sql
Returns
bool Whether $newLine contains end of the statement

Implements Wikimedia\Rdbms\IMaintainableDatabase.

Definition at line 848 of file DBConnRef.php.

◆ strreplace()

Wikimedia\Rdbms\DBConnRef::strreplace ( $orig,
$old,
$new )

Returns a SQL expression for simple string replacement (e.g.

REPLACE() in mysql)

Parameters
string$origColumn to modify
string$oldColumn to seek
string$newColumn to replace with
Returns
string

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 581 of file DBConnRef.php.

◆ tableExists()

Wikimedia\Rdbms\DBConnRef::tableExists ( $table,
$fname = __METHOD__ )

Query whether a given table exists.

Parameters
string$table
string$fname
Returns
bool
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IMaintainableDatabase.

Definition at line 375 of file DBConnRef.php.

◆ tableName()

Wikimedia\Rdbms\DBConnRef::tableName ( $name,
$format = 'quoted' )

Format a table name ready for use in constructing an SQL query.

This does two important things: it quotes the table names to clean them up, and it adds a table prefix if only given a table name with no quotes.

All functions of this object which require a table name call this function themselves. Pass the canonical name to such functions. This is only needed when calling query() directly.

Note
This function does not sanitize user input. It is not safe to use this function to escape user input.
Parameters
string$nameDatabase table name
string$formatOne of: quoted - Automatically pass the table name through addIdentifierQuotes() so that it can be used in a query. raw - Do not add identifier quotes to the table name
Returns
string Full database name

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 786 of file DBConnRef.php.

◆ tableNames()

Wikimedia\Rdbms\DBConnRef::tableNames ( $tables)

Fetch a number of table names into an associative array.

Much like tableName(), this is only needed when calling query() directly. Prefer calling other methods, or using SelectQueryBuilder.

Theoretical example (which really does not require raw SQL): [ 'user' => $user, 'watchlist' => $watchlist ] = $dbr->tableNames( 'user', 'watchlist' ); $sql = "SELECT wl_namespace, wl_title FROM $watchlist, $user WHERE wl_user=user_id AND wl_user=$nameWithQuotes";

Parameters
string...$tables
Returns
array
Deprecated
since 1.39; if you must format table names, write several calls to tableName or use tableNamesN instead of calling this function.

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 790 of file DBConnRef.php.

◆ tableNamesN()

Wikimedia\Rdbms\DBConnRef::tableNamesN ( $tables)

Fetch a number of table names into a zero-indexed numerical array.

Much like tableName(), this is only needed when calling query() directly. It is slightly more convenient than tableNames(), but you should still prefer calling other methods, or using SelectQueryBuilder.

Theoretical example (which really does not require raw SQL): [ $user, $watchlist ] = $dbr->tableNamesN( 'user', 'watchlist' ); $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user WHERE wl_user=user_id AND wl_user=$nameWithQuotes";

Parameters
string...$tables
Returns
array

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 794 of file DBConnRef.php.

◆ tablePrefix()

Wikimedia\Rdbms\DBConnRef::tablePrefix ( $prefix = null)

Get/set the table prefix.

Parameters
string | null$prefixThe table prefix to set, or omitted to leave it unchanged
Returns
string The previous table prefix

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 138 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call(), Wikimedia\Rdbms\DBConnRef\getDomainChangeException(), and Wikimedia\Rdbms\DatabaseDomain\newFromId().

◆ textFieldSize()

Wikimedia\Rdbms\DBConnRef::textFieldSize ( $table,
$field )

Returns the size of a text field, or -1 for "unlimited".

Parameters
string$table
string$field
Returns
int

Implements Wikimedia\Rdbms\IMaintainableDatabase.

Definition at line 844 of file DBConnRef.php.

◆ timestamp()

Wikimedia\Rdbms\DBConnRef::timestamp ( $ts = 0)

Convert a timestamp in one of the formats accepted by ConvertibleTimestamp to the format used for inserting into timestamp fields in this DBMS.

The result is unquoted, and needs to be passed through addQuotes() before it can be included in raw SQL.

Parameters
string | int$ts
Returns
string

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 688 of file DBConnRef.php.

◆ timestampOrNull()

Wikimedia\Rdbms\DBConnRef::timestampOrNull ( $ts = null)

Convert a timestamp in one of the formats accepted by ConvertibleTimestamp to the format used for inserting into timestamp fields in this DBMS.

If NULL is input, it is passed through, allowing NULL values to be inserted into timestamp fields.

The result is unquoted, and needs to be passed through addQuotes() before it can be included in raw SQL.

Parameters
string | int | null$ts
Returns
string|null

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 692 of file DBConnRef.php.

◆ truncate()

Wikimedia\Rdbms\DBConnRef::truncate ( $tables,
$fname = __METHOD__ )

Delete all data in a table(s) and reset any sequences owned by that table(s)

Parameters
string | string[]$tables
string$fname
Exceptions
DBErrorIf an error occurs
Since
1.35

Implements Wikimedia\Rdbms\IMaintainableDatabase.

Definition at line 828 of file DBConnRef.php.

◆ trxLevel()

Wikimedia\Rdbms\DBConnRef::trxLevel ( )

Gets the current transaction level.

Historically, transactions were allowed to be "nested". This is no longer supported, so this function really only returns a boolean.

Returns
int The previous value

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 126 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ trxTimestamp()

Wikimedia\Rdbms\DBConnRef::trxTimestamp ( )

Get the UNIX timestamp of the time that the transaction was established.

This can be used to reason about the staleness of SELECT data in REPEATABLE-READ transaction isolation level. Callers can assume that if a view-snapshot isolation is used, then the data read by SQL queries is at least up to date to that point (possibly more up-to-date since the first SELECT defines the snapshot).

Returns
float|null Returns null if there is not active transaction
Since
1.25

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 130 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ unionConditionPermutations()

Wikimedia\Rdbms\DBConnRef::unionConditionPermutations ( $table,
$vars,
array $permute_conds,
$extra_conds = '',
$fname = __METHOD__,
$options = [],
$join_conds = [] )

Construct a UNION query for permutations of conditions.

Databases sometimes have trouble with queries that have multiple values for multiple condition parameters combined with limits and ordering. This method constructs queries for the Cartesian product of the conditions and unions them all together.

See also
IDatabase::select()
Parameters
string | array$tableTable name
string | array$varsField names
array$permute_condsConditions for the Cartesian product. Keys are field names, values are arrays of the possible values for that field.
string | array$extra_condsAdditional conditions to include in the query.
string$fnameCaller function name
string | array$optionsQuery options. In addition to the options recognized by IDatabase::select(), the following may be used:
  • NOTALL: Set to use UNION instead of UNION ALL.
  • INNER ORDER BY: If specified and supported, subqueries will use this instead of ORDER BY.
string | array$join_condsJoin conditions
Returns
string SQL query string.
Since
1.30

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 570 of file DBConnRef.php.

◆ unionQueries()

Wikimedia\Rdbms\DBConnRef::unionQueries ( $sqls,
$all )

Construct a UNION query.

This is used for providing overload point for other DB abstractions not compatible with the MySQL syntax.

Parameters
array$sqlsSQL statements to combine
bool$allEither IDatabase::UNION_ALL or IDatabase::UNION_DISTINCT
Returns
string SQL fragment

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 566 of file DBConnRef.php.

◆ unionSupportsOrderAndLimit()

Wikimedia\Rdbms\DBConnRef::unionSupportsOrderAndLimit ( )

Determine if the RDBMS supports ORDER BY and LIMIT for separate subqueries within UNION.

Returns
bool

Implements Wikimedia\Rdbms\Platform\ISQLPlatform.

Definition at line 562 of file DBConnRef.php.

◆ unlock()

Wikimedia\Rdbms\DBConnRef::unlock ( $lockName,
$method )

Release a lock.

Named locks are not related to transactions

Parameters
string$lockNameName of lock to release
string$methodName of the calling method
Returns
bool Success
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 738 of file DBConnRef.php.

◆ update()

Wikimedia\Rdbms\DBConnRef::update ( $table,
$set,
$conds,
$fname = __METHOD__,
$options = [] )

Update all rows in a table that match a given condition.

Parameters
string$tableTable name
array$setCombination map/list where each string-keyed entry maps a column to a literal assigned value and each integer-keyed value is a SQL expression in the format of a column assignment within UPDATE...SET. The (column => value) entries are convenient due to automatic value quoting and conversion of null to NULL. The SQL assignment format is useful for updates like "column = column + X". All assignments have no defined execution order, so they should not depend on each other. Do not modify AUTOINCREMENT or UUID columns in assignments.
array | string$condsCondition in the format of IDatabase::select() conditions. In order to prevent possible performance or replication issues or damaging a data accidentally, an empty condition for 'update' queries isn't allowed. IDatabase::ALL_ROWS should be passed explicitly in order to update all rows.
string$fnameCalling function name (use METHOD) for logs/profiling
string | array$optionsCombination map/list where each string-keyed entry maps a non-boolean option to the option parameters and each integer-keyed value is the name of a boolean option. Supported options are:
  • IGNORE: Boolean: skip update of rows that would cause unique key conflicts. IDatabase::affectedRows() can be used to determine how many rows were updated.
Returns
bool Return true if no exception was thrown (deprecated since 1.33)
Exceptions
DBErrorIf an error occurs, {
See also
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 385 of file DBConnRef.php.

◆ upsert()

Wikimedia\Rdbms\DBConnRef::upsert ( $table,
array $rows,
$uniqueKeys,
array $set,
$fname = __METHOD__ )

Upsert row(s) into a table, in the provided order, while updating conflicting rows.

Conflicts are determined by the provided unique indexes. Note that it is possible for the provided rows to conflict even among themselves; it is preferable for the caller to de-duplicate such input beforehand.

See also
IDatabase::buildExcludedValue()
IDatabase::buildExcludedValue()
Parameters
string$tableTable name
array | array[]$rowsRow(s) to insert, in the form of either:
  • A string-keyed map of (column name => value) defining a new row. Values are treated as literals and quoted appropriately; null is interpreted as NULL. Columns belonging to a key in $uniqueKeys must be defined here and non-null.
  • An integer-keyed list of such string-keyed maps, defining a list of new rows. The keys in each map must be identical to each other and in the same order. The rows must not collide with each other.
string | string[] | string[][]$uniqueKeysColumn name or non-empty list of column name lists that define all applicable unique keys on the table. There must only be one such key. Each unique key on the table is "applicable" unless either:
  • It involves an AUTOINCREMENT column for which no values are assigned in $rows
  • It involves a UUID column for which newly generated UUIDs are assigned in $rows
array$setCombination map/list where each string-keyed entry maps a column to a literal assigned value and each integer-keyed value is a SQL assignment expression of the form "<unquoted alphanumeric column> = <SQL expression>". The (column => value) entries are convenient due to automatic value quoting and conversion of null to NULL. The SQL assignment entries are useful for updates like "column = column + X". All of the assignments have no defined execution order, so callers should make sure that they not depend on each other. Do not modify AUTOINCREMENT or UUID columns in assignments, even if they are just "secondary" unique keys. For multi-row upserts, use buildExcludedValue() to reference the value of a column from the corresponding row in $rows that conflicts with the current row.
string$fnameCalling function name (use METHOD) for logs/profiling
Returns
bool Return true if no exception was thrown (deprecated since 1.33)
Exceptions
DBErrorIf an error occurs, {
See also
query}
Since
1.22

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 531 of file DBConnRef.php.

◆ wasConnectionLoss()

Wikimedia\Rdbms\DBConnRef::wasConnectionLoss ( )

Determines if the last query error was due to a dropped connection.

Note that during a connection loss, the prior transaction will have been lost

Returns
bool
Since
1.31

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 593 of file DBConnRef.php.

◆ wasDeadlock()

Wikimedia\Rdbms\DBConnRef::wasDeadlock ( )

Determines if the last failure was due to a deadlock.

Note that during a deadlock, the prior transaction will have been lost

Returns
bool

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 585 of file DBConnRef.php.

◆ wasErrorReissuable()

Wikimedia\Rdbms\DBConnRef::wasErrorReissuable ( )

Determines if the last query error was due to something outside of the query itself.

Note that the transaction may have been lost, discarding prior writes and results

Returns
bool

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 601 of file DBConnRef.php.

◆ wasLockTimeout()

Wikimedia\Rdbms\DBConnRef::wasLockTimeout ( )

Determines if the last failure was due to a lock timeout.

Note that during a lock wait timeout, the prior transaction will have been lost

Returns
bool

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 589 of file DBConnRef.php.

◆ wasReadOnlyError()

Wikimedia\Rdbms\DBConnRef::wasReadOnlyError ( )

Determines if the last failure was due to the database being read-only.

Returns
bool

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 597 of file DBConnRef.php.

◆ writesOrCallbacksPending()

Wikimedia\Rdbms\DBConnRef::writesOrCallbacksPending ( )

Whether there is a transaction open with either possible write queries or unresolved pre-commit/commit/resolution callbacks pending.

This does not count recurring callbacks, e.g. from setTransactionListener().

Returns
bool

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 200 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

◆ writesPending()

Wikimedia\Rdbms\DBConnRef::writesPending ( )
Returns
bool Whether there is a transaction open with possible write queries
Since
1.27

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 196 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().


The documentation for this class was generated from the following file: