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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 $lb,$conn, $role) __destruct () Clean up the connection when out of scope. More... __toString () Get a debugging string that mentions the database type, the ID of this instance, and the ID of any underlying connection resource or driver object if one is present. More... addIdentifierQuotes ($s)
Escape a SQL identifier (e.g. More...

addQuotes ( $s) Escape and quote a raw value string for use in a SQL query. More... affectedRows () Get the number of rows affected by the last write query. More... anyChar () Returns a token for buildLike() that denotes a '_' to be used in a LIKE query. More... anyString () Returns a token for buildLike() that denotes a '' to be used in a LIKE query. More... begin ($fname=__METHOD__, $mode=IDatabase::TRANSACTION_EXPLICIT) Begin a transaction. More... bitAnd ($fieldLeft, $fieldRight) bitNot ($field)

bitOr ( $fieldLeft,$fieldRight)

buildConcat ( $stringList) Build a concatenation list to feed into a SQL query. More... buildGreatest ($fields, $values) Build a GREATEST function statement comparing columns/values. More... buildGroupConcatField ($delim, $table,$field, $conds='',$join_conds=[])
Build a GROUP_CONCAT or equivalent statement for a query. More...

buildIntegerCast ( $field) buildLeast ($fields, $values) Build a LEAST function statement comparing columns/values. More... buildLike ($param,... $params) LIKE statement wrapper. More... buildSelectSubquery ($table, $vars,$conds='', $fname=__METHOD__,$options=[], $join_conds=[]) Equivalent to IDatabase::selectSQLText() except wraps the result in Subquery. More... buildStringCast ($field)

buildSubstring ( $input,$startPosition, $length=null) cancelAtomic ($fname=__METHOD__, AtomicSectionIdentifier $sectionId=null) Cancel an atomic section of SQL statements. More... clearFlag ($flag, $remember=self::REMEMBER_NOTHING) Clear a flag for this connection. More... close ($fname=__METHOD__, $owner=null) Close the database connection. More... commit ($fname=__METHOD__, $flush=self::FLUSHING_ONE) Commits a transaction previously started using begin() More... conditional ($cond, $caseTrueExpression,$caseFalseExpression)
Returns an SQL expression for a simple conditional. More...

databasesAreIndependent ()
Returns true if DBs are assumed to be on potentially different servers. More...

dbSchema ( $schema=null) Get/set the db schema. More... decodeBlob ($b)
Some DBMSs return a special placeholder object representing blob fields in result objects. More...

decodeExpiry ( $expiry,$format=TS_MW)
Decode an expiry time into a DBMS independent format. More...

delete ( $table,$conds, $fname=__METHOD__) Delete all rows in a table that match a condition. More... deleteJoin ($delTable, $joinTable,$delVar, $joinVar,$conds, $fname=__METHOD__) DELETE where the condition is a join. More... doAtomicSection ($fname, callable $callback,$cancelable=self::ATOMIC_NOT_CANCELABLE)
Perform an atomic section of reversible SQL statements from a callback. More...

encodeBlob ( $b) Some DBMSs have a special format for inserting into blob fields, they don't allow simple quoted strings to be inserted. More... encodeExpiry ($expiry)
Encode an expiry time into the DBMS dependent format. More...

endAtomic ( $fname=__METHOD__) Ends an atomic section of SQL statements. More... estimateRowCount ($tables, $vars=' *',$conds='', $fname=__METHOD__,$options=[], $join_conds=[]) Estimate the number of rows in dataset. More... explicitTrxActive () Check whether there is a transaction open at the specific request of a caller. More... factorConds ($condsArray)
Given an array of condition arrays representing an OR list of AND lists, for example: More...

fetchObject ( $res) fetchRow ($res)

fieldExists ( $table,$field, $fname=__METHOD__) Determines whether a field exists in a table. More... flushSnapshot ($fname=__METHOD__, $flush=self::FLUSHING_ONE) Commit any transaction but error out if writes or callbacks are pending. More... freeResult ($res)

getDBname ()
Get the current database name; null if there isn't one. More...

getDomainID ()
Return the currently selected domain ID. More...

getFlag ( $flag) Returns a boolean whether the flag$flag is set for this connection. More...

getInfinity ()
Find out when 'infinity' is. More...

getLag ()
Get the amount of replication lag for this database server. More...

getLBInfo ( $name=null) Get properties passed down from the server info array of the load balancer. More... getPrimaryPos () Get the position of this primary DB. More... getProperty ($name)

getReferenceRole ()

getReplicaPos ()
Get the replication position of this replica DB. More...

getScopedLockAndFlush ( $lockKey,$fname, $timeout) Acquire a named lock, flush any transaction, and return an RAII style unlocker object. More... getServer () Get the hostname or IP address of the server. More... getServerInfo () Get a human-readable string describing the current software version. More... getServerName () Get the readable name for the server. More... getServerVersion () A string describing the current software version, like from mysql_get_server_info() More... getSessionLagStatus () Get the replica DB lag when the current transaction started or a general lag estimate if not transaction is active. More... getSoftwareLink () Returns a wikitext style link to the DB's website (e.g. More... getTopologyBasedServerId () Get a non-recycled ID that uniquely identifies this server within the replication topology. More... getTopologyRole () Get the replication topology role of this server. More... getTopologyRootPrimary () Get the readable name of the sole root primary DB server for the replication topology. More... getType () Get the RDBMS type of the server (e.g. More... implicitOrderby () Returns true if this database does an implicit order by when the column has an index For example: SELECT page_title FROM page LIMIT 1. More... indexExists ($table, $index,$fname=__METHOD__)
Determines whether an index exists. More...

insert ( $table,$rows, $fname=__METHOD__,$options=[])
Insert the given row(s) into a table. More...

insertId ()
Get the inserted value of an auto-increment row. More...

insertSelect ( $destTable,$srcTable, $varMap,$conds, $fname=__METHOD__,$insertOptions=[], $selectOptions=[],$selectJoinConds=[])
INSERT SELECT wrapper. More...

isOpen ()

lastDoneWrites ()
Get the last time the connection may have been used for a write query. More...

lastErrno ()
Get the last error number. More...

lastError ()
Get a description of the last error. More...

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

limitResult ( $sql,$limit, $offset=false) Construct a LIMIT query with optional offset. More... lock ($lockName, $method,$timeout=5, $flags=0) Acquire a named lock. More... lockForUpdate ($table, $conds='',$fname=__METHOD__, $options=[],$join_conds=[])
Lock all rows meeting the given conditions/options FOR UPDATE. More...

lockIsFree ( $lockName,$method)
Check to see if a named lock is not locked by any thread (non-blocking) More...

makeList (array $a,$mode=self::LIST_COMMA)
Makes an encoded list of strings from an array. More...

makeWhereFrom2d ( $data,$baseKey, $subKey) Build a partial where clause from a 2-d array such as used for LinkBatch. More... namedLocksEnqueue () Check to see if a named lock used by lock() use blocking queues. More... newSelectQueryBuilder () Create an empty SelectQueryBuilder which can be used to run queries against this connection. More... nextSequenceValue ($seqName)
Deprecated method, calls should be removed. More...

numRows ( $res) onAtomicSectionCancel (callable$callback, $fname=__METHOD__) Run a callback when the atomic section is cancelled. More... onTransactionCommitOrIdle (callable$callback, $fname=__METHOD__) Run a callback when the current transaction commits or now if there is none. More... onTransactionPreCommitOrIdle (callable$callback, $fname=__METHOD__) Run a callback before the current transaction commits or now if there is none. More... onTransactionResolution (callable$callback, $fname=__METHOD__) Run a callback when the current transaction commits or rolls back. More... pendingWriteCallers () Get the list of method names that did write queries for this transaction. More... pendingWriteQueryDuration ($type=self::ESTIMATE_TOTAL)
Get the time spend running write queries for this transaction. More...

ping (&$rtt=null) Ping the server and try to reconnect if it there is no connection. More... primaryPosWait (DBPrimaryPos$pos, $timeout) Wait for the replica DB to catch up to a given primary DB position. More... query ($sql, $fname=__METHOD__,$flags=0)
Run an SQL query and return the result. More...

replace ( $table,$uniqueKeys, $rows,$fname=__METHOD__)
Insert row(s) into a table, deleting all conflicting rows beforehand. More...

restoreFlags ( $state=self::RESTORE_PRIOR) Restore the flags to their prior state before the last setFlag/clearFlag call. More... rollback ($fname=__METHOD__, $flush=self::FLUSHING_ONE) Rollback a transaction previously started using begin() More... select ($table, $vars,$conds='', $fname=__METHOD__,$options=[], $join_conds=[]) Execute a SELECT query constructed using the various parameters provided. More... selectDB ($db)
Change the current database. More...

selectDomain ( $domain) Set the current domain (database, schema, and table prefix) More... selectField ($table, $var,$cond='', $fname=__METHOD__,$options=[], $join_conds=[]) A SELECT wrapper which returns a single field from a single result row. More... selectFieldValues ($table, $var,$cond='', $fname=__METHOD__,$options=[], $join_conds=[]) A SELECT wrapper which returns a list of single field values from result rows. More... selectRow ($table, $vars,$conds, $fname=__METHOD__,$options=[], $join_conds=[]) Wrapper to IDatabase::select() that only fetches one row (via LIMIT) More... selectRowCount ($tables, $vars=' *',$conds='', $fname=__METHOD__,$options=[], $join_conds=[]) Get the number of rows in dataset. More... selectSQLText ($table, $vars,$conds='', $fname=__METHOD__,$options=[], $join_conds=[]) Take the same arguments as IDatabase::select() and return the SQL it would use. More... serverIsReadOnly () setBigSelects ($value=true)
Allow or deny "big selects" for this session only. More...

setFlag ( $flag,$remember=self::REMEMBER_NOTHING)
Set a flag for this connection. More...

setIndexAliases (array $aliases) Convert certain index names to alternative names before querying the DB. More... setLBInfo ($nameOrArray, $value=null) Set the entire array or a particular key of the managing load balancer info array. More... setSchemaVars ($vars)
Set schema variables to be used when streaming commands from SQL files or stdin. More...

setSessionOptions (array $options) Override database's default behavior. More... setTableAliases (array$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. More...

setTransactionListener ( $name, callable$callback=null)
Run a callback after each time any transaction commits or rolls back. More...

startAtomic ( $fname=__METHOD__,$cancelable=IDatabase::ATOMIC_NOT_CANCELABLE)
Begin an atomic section of SQL statements. More...

strreplace ( $orig,$old, $new) Returns a SQL expression for simple string replacement (e.g. More... tableExists ($table, $fname=__METHOD__) Query whether a given table exists. More... tablePrefix ($prefix=null)
Get/set the table prefix. More...

timestamp ( $ts=0) Convert a timestamp in one of the formats accepted by ConvertibleTimestamp to the format used for inserting into timestamp fields in this DBMS. More... timestampOrNull ($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. More...

trxLevel ()
Gets the current transaction level. More...

trxTimestamp ()
Get the UNIX timestamp of the time that the transaction was established. More...

unionConditionPermutations ( $table,$vars, array $permute_conds,$extra_conds='', $fname=__METHOD__,$options=[], $join_conds=[]) Construct a UNION query for permutations of conditions. More... unionQueries ($sqls, $all) Construct a UNION query. More... unionSupportsOrderAndLimit () Determine if the RDBMS supports ORDER BY and LIMIT for separate subqueries within UNION. More... unlock ($lockName, $method) Release a lock. More... update ($table, $set,$conds, $fname=__METHOD__,$options=[])
Update all rows in a table that match a given condition. More...

upsert ( $table, array$rows, $uniqueKeys, array$set, $fname=__METHOD__) Upsert the given row(s) into a table. More... wasConnectionLoss () Determines if the last query error was due to a dropped connection. More... wasDeadlock () Determines if the last failure was due to a deadlock. More... wasErrorReissuable () Determines if the last query error was due to something outside of the query itself. More... wasLockTimeout () Determines if the last failure was due to a lock timeout. More... wasReadOnlyError () Determines if the last failure was due to the database being read-only. More... writesOrCallbacksPending () Whether there is a transaction open with either possible write queries or unresolved pre-commit/commit/resolution callbacks pending. More... writesPending () Public Member Functions inherited from Wikimedia\Rdbms\IDatabase buildSubString ($input, $startPosition,$length=null)
Build a SUBSTRING function. More...

fetchObject (IResultWrapper $res) Fetch the next row from the given result object, in object form. More... fetchRow (IResultWrapper$res)
Fetch the next row from the given result object, in associative array form. More...

freeResult (IResultWrapper $res) Free a result object returned by query() or select() More... ## Protected Member Functions assertRoleAllowsWrites () Error out if the role is not DB_PRIMARY. More... getDomainChangeException () ## Private Attributes Database null$conn
Live connection handle. More...

ILoadBalancer $lb array$params
N-tuple of (server index, group, DatabaseDomain|string) More...

int $role One of DB_PRIMARY/DB_REPLICA. More... const FLD_DOMAIN = 2 const FLD_FLAGS = 3 const FLD_GROUP = 1 const FLD_INDEX = 0 ## Additional Inherited Members Public Attributes inherited from Wikimedia\Rdbms\IDatabase const LOCK_TIMESTAMP = 1 Flag to return the lock acquisition timestamp (null if not acquired) More... ## Detailed Description Helper class used for automatically marking an IDatabase connection as reusable (once it no longer matters which DB domain is selected) and for deferring the actual network connection. This uses an RAII-style pattern where calling code is expected to keep the returned reference handle as a function variable that falls out of scope when no longer needed. This avoids the need for matching reuseConnection() calls for every "return" statement as well as the tedious use of try/finally. Example: function getRowData() {$conn = $this->lb->getConnectedRef( DB_REPLICA );$row = $conn->select( ... ); return$row ? (array)$row : false; //$conn falls out of scope and $this->lb->reuseConnection() gets called } Since 1.22 Definition at line 30 of file DBConnRef.php. ## Constructor & Destructor Documentation ## ◆ __construct()  Wikimedia\Rdbms\DBConnRef::__construct ( ILoadBalancer$lb, $conn,$role )
Parameters
 ILoadBalancer $lb Connection manager for$conn IDatabase | array $conn Database or (server index, query groups, domain, flags) int$role The type of connection asked for; one of DB_PRIMARY/DB_REPLICA
Access: internal
This method should not be called outside of LoadBalancer

Definition at line 51 of file DBConnRef.php.

## ◆ __destruct()

 Wikimedia\Rdbms\DBConnRef::__destruct ( )

Clean up the connection when out of scope.

Definition at line 801 of file DBConnRef.php.

## ◆ __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 758 of file DBConnRef.php.

 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\IDatabase.

Definition at line 483 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

 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\IDatabase.

Definition at line 479 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ 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 265 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\IDatabase.

Definition at line 491 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ 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\IDatabase.

Definition at line 495 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ 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

Definition at line 779 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 $fname Calling function name string$mode A situationally valid IDatabase::TRANSACTION_* constant [optional]
Exceptions
 DBError If an error occurs, {
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 648 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ bitAnd()

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

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 400 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ bitNot()

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

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 396 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ bitOr()

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

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 404 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ buildConcat()

 Wikimedia\Rdbms\DBConnRef::buildConcat ( $stringList ) Build a concatenation list to feed into a SQL query. Parameters  string[]$stringList Raw SQL expression list; caller is responsible for escaping
Returns
string

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 408 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ 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[] $fields Name(s) of column(s) with values to compare string | int | float | string[] | int[] | float[]$values Values to compare
Returns
mixed
Since
1.35

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 418 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ buildGroupConcatField()

 Wikimedia\Rdbms\DBConnRef::buildGroupConcatField ( $delim,$table, $field,$conds = '', $join_conds = [] ) Build a GROUP_CONCAT or equivalent statement for a query. This is useful for combining a field for several rows into a single string. NULL values will not appear in the output, duplicated values will appear, and the resulting delimiter-separated values have no defined sort order. Code using the results may need to use the PHP unique() or sort() methods. Parameters  string$delim Glue to bind the results together string | array $table Table name string$field Field name string | array $conds Conditions string | array$join_conds Join conditions
Returns
string SQL text
Since
1.23

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 412 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ buildIntegerCast()

 Wikimedia\Rdbms\DBConnRef::buildIntegerCast ( $field ) Parameters  string$field Field or column to cast
Returns
string
Since
1.31

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 434 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ 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[] $fields Name(s) of column(s) with values to compare string | int | float | string[] | int[] | float[]$values Values to compare
Returns
mixed
Since
1.35

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 422 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ 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.

Parameters
 string $field Field or column to cast Returns string Since 1.28 Implements Wikimedia\Rdbms\IDatabase. Definition at line 430 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ buildSubstring()  Wikimedia\Rdbms\DBConnRef::buildSubstring ($input, $startPosition,$length = null )

Definition at line 426 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ 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
IDatabase::startAtomic
Parameters
 string $fname AtomicSectionIdentifier | null$sectionId Section ID from startAtomic(); passing this enables cancellation of unclosed nested sections [optional]
Exceptions
 DBError If an error occurs, {
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 636 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ clearFlag()

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

Clear a flag for this connection.

Parameters
 int $flag One of (IDatabase::DBO_DEBUG, IDatabase::DBO_TRX) string$remember IDatabase::REMEMBER_* constant [default: REMEMBER_NOTHING]

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 180 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ close()

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

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.

Parameters
 string $fname Caller name int | null$owner ID of the calling instance (e.g. the LBFactory ID)
Returns
bool Success
Exceptions

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 277 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 $fname string$flush Flush 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
 DBError If an error occurs, {
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 652 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ conditional()

 Wikimedia\Rdbms\DBConnRef::conditional ( $cond,$caseTrueExpression, $caseFalseExpression ) Returns an SQL expression for a simple conditional. This doesn't need to be overridden unless CASE isn't supported in the RDBMS. Parameters  string | array$cond SQL condition expression (yields a boolean) string $caseTrueExpression SQL expression to return when the condition is true string$caseFalseExpression SQL expression to return when the condition is false
Returns
string SQL fragment

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 557 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ 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 445 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ dbSchema()

 Wikimedia\Rdbms\DBConnRef::dbSchema ( $schema = null ) Get/set the db schema. Parameters  string | null$schema The database schema to set, or omitted to leave it unchanged
Returns
string The previous db schema

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 121 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

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 690 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ decodeExpiry()

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

Decode an expiry time into a DBMS independent format.

Parameters
 string $expiry DB timestamp field value for expiry int$format TS_* constant, defaults to TS_MW
Returns
string

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 738 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

 Wikimedia\Rdbms\DBConnRef::delete ( $table,$conds, $fname = __METHOD__ ) Delete all rows in a table that match a condition. Parameters  string$table Table name string | array $conds Array of conditions. See$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 $fname Name of the calling function Returns bool Return true if no exception was thrown (deprecated since 1.33) Exceptions  DBError If an error occurs, { See also query} Implements Wikimedia\Rdbms\IDatabase. Definition at line 527 of file DBConnRef.php. ## ◆ deleteJoin()  Wikimedia\Rdbms\DBConnRef::deleteJoin ($delTable, $joinTable,$delVar, $joinVar,$conds, $fname = __METHOD__ ) DELETE where the condition is a join. MySQL overrides this to use a multi-table DELETE syntax, in other databases we use sub-selects For safety, an empty$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 $delTable The table to delete from. string$joinTable The other table. string $delVar The variable to join on, in the first table. string$joinVar The variable to join on, in the second table. array | string $conds Condition array of field names mapped to variables, ANDed together in the WHERE clause string$fname Calling function name (use METHOD) for logs/profiling
Exceptions
 DBError If an error occurs, {
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 519 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__ );
Database::startAtomic
Database::endAtomic
Database::cancelAtomic
Parameters
 string $fname Caller name (usually METHOD) callable$callback Callback that issues DB updates string $cancelable Pass self::ATOMIC_CANCELABLE to use a savepoint and enable self::cancelAtomic() for this section. Returns mixed Result of the callback (since 1.28) Exceptions  DBError If an error occurs, { See also query} Exceptions  Exception If an error occurs in the callback Since 1.27; prior to 1.31 this did a rollback() instead of cancelAtomic(), and assumed no callers up the stack would ever try to catch the exception. Implements Wikimedia\Rdbms\IDatabase. Definition at line 641 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ encodeBlob()  Wikimedia\Rdbms\DBConnRef::encodeBlob ($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 $b Returns string|Blob Exceptions Implements Wikimedia\Rdbms\IDatabase. Definition at line 686 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ encodeExpiry()  Wikimedia\Rdbms\DBConnRef::encodeExpiry ($expiry )

Encode an expiry time into the DBMS dependent format.

Parameters
 string $expiry Timestamp for expiry, or the 'infinity' string Returns string Implements Wikimedia\Rdbms\IDatabase. Definition at line 734 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ endAtomic()  Wikimedia\Rdbms\DBConnRef::endAtomic ($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
IDatabase::startAtomic
Parameters
 string $fname Exceptions  DBError If an error occurs, { See also query} Implements Wikimedia\Rdbms\IDatabase. Definition at line 631 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ estimateRowCount()  Wikimedia\Rdbms\DBConnRef::estimateRowCount ($tables, $var = ' *',$conds = '', $fname = __METHOD__,$options = [], $join_conds = [] ) Estimate the number of rows in dataset. MySQL allows you to estimate the number of rows that would be returned by a SELECT query, using EXPLAIN SELECT. The estimate is provided using index cardinality statistics, and is notoriously inaccurate, especially when large numbers of rows have recently been added or deleted. For DBMSs that don't support fast result size estimation, this function will actually perform the SELECT COUNT(*). Takes the same arguments as IDatabase::select(). Parameters  string | string[]$tables Table name(s) string $var Column for which NULL values are not counted [default "*"] array | string$conds Filters on the table string $fname Function name for profiling array$options Options for select array | string $join_conds Join conditions Returns int Row count Exceptions  DBError If an error occurs, { See also query} Implements Wikimedia\Rdbms\IDatabase. Definition at line 340 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ explicitTrxActive()  Wikimedia\Rdbms\DBConnRef::explicitTrxActive ( ) Check whether there is a transaction open at the specific request of a caller. Explicit transactions are spawned by begin(), startAtomic(), and doAtomicSection(). Note that explicit transactions should not be confused with explicit transaction rounds. Returns bool Since 1.28 Implements Wikimedia\Rdbms\IDatabase. Definition at line 104 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ factorConds()  Wikimedia\Rdbms\DBConnRef::factorConds ($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 $condsArray An array of associative arrays. The associative array keys represent field names, and the values represent the field values to compare against. Returns string SQL expression fragment Implements Wikimedia\Rdbms\IDatabase. Definition at line 392 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ fetchObject()  Wikimedia\Rdbms\DBConnRef::fetchObject ($res )
Deprecated:
since 1.37 use IResultWrapper::fetchObject()
Parameters
 IResultWrapper $res Returns stdClass|bool Definition at line 228 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(), and wfDeprecated(). ## ◆ fetchRow()  Wikimedia\Rdbms\DBConnRef::fetchRow ($res )
Deprecated:
since 1.37 use IResultWrapper::fetchRow()
Parameters
 IResultWrapper $res Returns array|bool Definition at line 238 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(), and wfDeprecated(). ## ◆ fieldExists()  Wikimedia\Rdbms\DBConnRef::fieldExists ($table, $field,$fname = __METHOD__ )

Determines whether a field exists in a table.

Parameters
 string $table Table name string$field Filed to check on that table string $fname Calling function name (optional) Returns bool Whether$table has filed $field Exceptions  DBError If an error occurs, { See also query} Implements Wikimedia\Rdbms\IDatabase. Definition at line 360 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ flushSnapshot()  Wikimedia\Rdbms\DBConnRef::flushSnapshot ($fname = __METHOD__, $flush = self::FLUSHING_ONE ) Commit any transaction but error out if writes or callbacks are pending. This is intended for clearing out REPEATABLE-READ snapshots so that callers can see a new point-in-time of the database. This is useful when one of many transaction rounds finished and significant time will pass in the script's lifetime. It is also useful to call on a replica DB after waiting on replication to catch up to the primary DB. Parameters  string$fname Calling function name string $flush Flush flag, set to situationally valid IDatabase::FLUSHING_* constant to disable warnings about explicitly committing implicit transactions, or calling commit when no transaction is in progress. This will trigger an exception if there is an ongoing explicit transaction. Only set the flush flag if you are sure that these warnings are not applicable, and no explicit transactions are open. Exceptions  DBError If an error occurs, { See also query} Since 1.28 1.34 Added$flush parameter

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 660 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ freeResult()

 Wikimedia\Rdbms\DBConnRef::freeResult ( $res ) Deprecated: since 1.37 Use IResultWrapper::free() Parameters  IResultWrapper$res A SQL result

Definition at line 294 of file DBConnRef.php.

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

## ◆ 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 461 of file DBConnRef.php.

## ◆ getDomainChangeException()

 Wikimedia\Rdbms\DBConnRef::getDomainChangeException ( )
protected
Returns
DBUnexpectedError

Definition at line 789 of file DBConnRef.php.

## ◆ 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 196 of file DBConnRef.php.

## ◆ getFlag()

 Wikimedia\Rdbms\DBConnRef::getFlag ( $flag ) Returns a boolean whether the flag$flag is set for this connection.

Parameters
 int $flag One of the class IDatabase::DBO_* constants Returns bool Implements Wikimedia\Rdbms\IDatabase. Definition at line 188 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ getInfinity()  Wikimedia\Rdbms\DBConnRef::getInfinity ( ) Find out when 'infinity' is. Most DBMSes support this. This is a special keyword for timestamps in PostgreSQL, and works with CHAR(14) as well because "i" sorts after all numbers. Returns string Implements Wikimedia\Rdbms\IDatabase. Definition at line 730 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ getLag()  Wikimedia\Rdbms\DBConnRef::getLag ( ) Get the amount of replication lag for this database server. Callers should avoid using this method while a transaction is active Returns float|int|false Database replication lag in seconds or false on error Exceptions  DBError If an error occurs, { See also query} Implements Wikimedia\Rdbms\IDatabase. Definition at line 678 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ getLBInfo()  Wikimedia\Rdbms\DBConnRef::getLBInfo ($name = null )

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

Parameters
 string | null $name The entry of the info array to get, or null to get the whole array Returns array|mixed|null Implements Wikimedia\Rdbms\IDatabase. Definition at line 134 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ getPrimaryPos()  Wikimedia\Rdbms\DBConnRef::getPrimaryPos ( ) Get the position of this primary DB. Returns DBPrimaryPos|bool False if this is not a primary DB Exceptions  DBError If an error occurs, { See also query} Since 1.37 Implements Wikimedia\Rdbms\IDatabase. Definition at line 593 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ getProperty()  Wikimedia\Rdbms\DBConnRef::getProperty ($name )

Definition at line 192 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 76 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\$role. ## ◆ getReplicaPos()  Wikimedia\Rdbms\DBConnRef::getReplicaPos ( ) Get the replication position of this replica DB. Returns DBPrimaryPos|bool False if this is not a replica DB Exceptions  DBError If an error occurs, { See also query} Implements Wikimedia\Rdbms\IDatabase. Definition at line 589 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ 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 $lockKey Name of lock to release string$fname Name of the calling method int $timeout Acquisition timeout in seconds Returns ScopedCallback|null Exceptions  DBError If an error occurs, { See also query} Since 1.27 Implements Wikimedia\Rdbms\IDatabase. Definition at line 720 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 471 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ 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 80 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 475 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ 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 273 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  DBError If an error occurs, { See also query} Since 1.27 Implements Wikimedia\Rdbms\IDatabase. Definition at line 682 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ 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 269 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ 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 Since 1.37 Implements Wikimedia\Rdbms\IDatabase. Definition at line 84 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 Since 1.34 Implements Wikimedia\Rdbms\IDatabase. Definition at line 88 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ getTopologyRootPrimary()  Wikimedia\Rdbms\DBConnRef::getTopologyRootPrimary ( ) Get the readable name of the sole root primary DB server for 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 Readable server name; null if unknown or if co-primaries are defined Exceptions Since 1.37 Implements Wikimedia\Rdbms\IDatabase. Definition at line 92 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 206 of file DBConnRef.php. Referenced by Wikimedia\Rdbms\DBConnRef\__toString(). ## ◆ 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\IDatabase. Definition at line 144 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 $fname Returns bool|null Exceptions  DBError If an error occurs, { See also query} Implements Wikimedia\Rdbms\IDatabase. Definition at line 364 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ insert()  Wikimedia\Rdbms\DBConnRef::insert ($table, $rows,$fname = __METHOD__, $options = [] ) Insert the given row(s) into a table. Parameters  string$table Table name array | array[] $rows Row(s) to insert, as either: A string-keyed map of (column name => value) defining a new row. Values are treated as literals and quoted appropriately; null is interpreted as NULL. An integer-keyed list of such string-keyed maps, defining a list of new rows. The keys in each map must be identical to each other and in the same order. The rows must not collide with each other. string$fname Calling function name (use METHOD) for logs/profiling string | array $options Combination map/list where each string-keyed entry maps a non-boolean option to the option parameters and each integer-keyed value is the name of a boolean option. Supported options are: IGNORE: Boolean: skip insertion of rows that would cause unique key conflicts. IDatabase::affectedRows() can be used to determine how many rows were inserted. Returns bool Return true if no exception was thrown (deprecated since 1.33) Exceptions  DBError If an error occurs, { See also query} Implements Wikimedia\Rdbms\IDatabase. Definition at line 372 of file DBConnRef.php. ## ◆ insertId()  Wikimedia\Rdbms\DBConnRef::insertId ( ) Get the inserted value of an auto-increment row. This should only be called after an insert that used an auto-incremented value. If no such insert was previously done in the current database session, the return value is undefined. Returns int Implements Wikimedia\Rdbms\IDatabase. Definition at line 253 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ insertSelect()  Wikimedia\Rdbms\DBConnRef::insertSelect ($destTable, $srcTable,$varMap, $conds,$fname = __METHOD__, $insertOptions = [],$selectOptions = [], $selectJoinConds = [] ) INSERT SELECT wrapper. Warning If the insert will use an auto-increment or sequence to determine the value of a column, this may break replication on databases using statement-based replication if the SELECT is not deterministically ordered. Parameters  string$destTable The table name to insert into string | array $srcTable May be either a table name, or an array of table names to include in a join. array$varMap Must 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 $conds Condition array. See$conds in IDatabase::select() for the details of the format of condition arrays. May be "*" to copy the whole table. string $fname The function name of the caller, from METHOD array$insertOptions Options 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 $selectOptions Options for the SELECT part of the query, see IDatabase::select() for details. array$selectJoinConds Join 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
 DBError If an error occurs, {
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 533 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 172 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

Returns
bool Whether this DB is read-only
Since
1.27

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 746 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ lastDoneWrites()

 Wikimedia\Rdbms\DBConnRef::lastDoneWrites ( )

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

Returns
int|float UNIX timestamp or false
Since
1.24

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 152 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ lastErrno()

 Wikimedia\Rdbms\DBConnRef::lastErrno ( )

Get the last error number.

https://www.php.net/mysql_errno
Returns
int

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 257 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ lastError()

 Wikimedia\Rdbms\DBConnRef::lastError ( )

Get a description of the last error.

https://www.php.net/mysql_error
Returns
string

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 261 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 148 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 $sql SQL query we will append the limit too int$limit The SQL limit int | bool $offset The SQL offset (default false) Returns string Since 1.34 Implements Wikimedia\Rdbms\IDatabase. Definition at line 329 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ lock()  Wikimedia\Rdbms\DBConnRef::lock ($lockName, $method,$timeout = 5, $flags = 0 ) Acquire a named lock. Named locks are not related to transactions Parameters  string$lockName Name of lock to acquire string $method Name of the calling method int$timeout Acquisition timeout in seconds (0 means non-blocking) int $flags Bit field of IDatabase::LOCK_* constants Returns bool Success Exceptions  DBError If an error occurs, { See also query} Implements Wikimedia\Rdbms\IDatabase. Definition at line 708 of file DBConnRef.php. ## ◆ lockForUpdate()  Wikimedia\Rdbms\DBConnRef::lockForUpdate ($table, $conds = '',$fname = __METHOD__, $options = [],$join_conds = [] )

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

Parameters
 string | string[] $table Table name(s) array | string$conds Filters on the table string $fname Function name for profiling array$options Options for select ("FOR UPDATE" is added automatically) array $join_conds Join conditions Returns int Number of matching rows found (and locked) Exceptions  DBError If an error occurs, { See also query} Since 1.32 Implements Wikimedia\Rdbms\IDatabase. Definition at line 352 of file DBConnRef.php. ## ◆ lockIsFree()  Wikimedia\Rdbms\DBConnRef::lockIsFree ($lockName, $method ) Check to see if a named lock is not locked by any thread (non-blocking) Parameters  string$lockName Name of lock to poll string $method Name of method calling us Returns bool Exceptions  DBError If an error occurs, { See also query} Since 1.20 Implements Wikimedia\Rdbms\IDatabase. Definition at line 702 of file DBConnRef.php. ## ◆ makeList()  Wikimedia\Rdbms\DBConnRef::makeList ( array$a, $mode = self::LIST_COMMA ) Makes an encoded list of strings from an array. These can be used to make conjunctions or disjunctions on SQL condition strings derived from an array ({ See also select}$conds documentation).

Example usage:

$sql =$db->makeList( [
'rev_page' => $id,$db->makeList( [ 'rev_minor' => 1, 'rev_len < 500' ], $db::LIST_OR ) This would set$sql to "rev_page = '$id' AND (rev_minor = 1 OR rev_len < 500)" Parameters  array$a Containing the data int $mode IDatabase class constant: IDatabase::LIST_COMMA: Comma separated, no field names IDatabase::LIST_AND: ANDed WHERE clause (without the WHERE). IDatabase::LIST_OR: ORed WHERE clause (without the WHERE) IDatabase::LIST_SET: Comma separated with field names, like a SET clause IDatabase::LIST_NAMES: Comma separated field names Exceptions  DBError If an error occurs, { See also query} Returns string Implements Wikimedia\Rdbms\IDatabase. Definition at line 384 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ makeWhereFrom2d()  Wikimedia\Rdbms\DBConnRef::makeWhereFrom2d ($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 $data Organized as 2-d [ baseKeyVal => [ subKeyVal => [ignored], ... ], ... ] string$baseKey Field name to match the base-level keys to (eg 'pl_namespace') string $subKey Field name to match the sub-level keys to (eg 'pl_title') Returns string|bool SQL fragment, or false if no items in array Implements Wikimedia\Rdbms\IDatabase. Definition at line 388 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ namedLocksEnqueue()  Wikimedia\Rdbms\DBConnRef::namedLocksEnqueue ( ) Check to see if a named lock used by lock() use blocking queues. Returns bool Since 1.26 Implements Wikimedia\Rdbms\IDatabase. Definition at line 726 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ newSelectQueryBuilder()  Wikimedia\Rdbms\DBConnRef::newSelectQueryBuilder ( ) Create an empty SelectQueryBuilder which can be used to run queries against this connection. Returns SelectQueryBuilder Implements Wikimedia\Rdbms\IDatabase. Definition at line 299 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ nextSequenceValue()  Wikimedia\Rdbms\DBConnRef::nextSequenceValue ($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 $seqName Returns null|NextSequenceValue Implements Wikimedia\Rdbms\IDatabase. Definition at line 499 of file DBConnRef.php. ## ◆ numRows()  Wikimedia\Rdbms\DBConnRef::numRows ($res )
Deprecated:
since 1.37 use IResultWrapper::numRows()
Parameters
 IResultWrapper | bool $res A SQL result Returns int Implements Wikimedia\Rdbms\IDatabase. Definition at line 248 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(), and wfDeprecated(). ## ◆ onAtomicSectionCancel()  Wikimedia\Rdbms\DBConnRef::onAtomicSectionCancel ( callable$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 $fname Caller name Since 1.34 Implements Wikimedia\Rdbms\IDatabase. Definition at line 616 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ onTransactionCommitOrIdle()  Wikimedia\Rdbms\DBConnRef::onTransactionCommitOrIdle ( callable$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 $fname Caller name Exceptions  DBError If an error occurs, { See also query} Exceptions  Exception If the callback runs immediately and an error occurs in it Since 1.32 Implements Wikimedia\Rdbms\IDatabase. Definition at line 606 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ onTransactionPreCommitOrIdle()  Wikimedia\Rdbms\DBConnRef::onTransactionPreCommitOrIdle ( callable$callback, $fname = __METHOD__ ) Run a callback before the current transaction commits or now if there is none. If there is a transaction and it is rolled back, then the callback is cancelled. When transaction round mode (DBO_TRX) is set, the callback will run at the end of the round, just after all peer transactions COMMIT. If the transaction round is rolled back, then the callback is cancelled. If there is no current transaction, one will be created to wrap the callback. Callbacks cannot use begin()/commit() to manage transactions. The use of other IDatabase handles from the callback should be avoided. Use this method only for the following purposes: • a) RDBMS updates, prone to lock timeouts/deadlocks, that require atomicity with respect to the updates in the current transaction (if any) • b) Purges to lightweight cache services due to RDBMS updates The callback takes the one argument: Callbacks will execute in the order they were enqueued. Parameters  callable$callback string $fname Caller name Exceptions  DBError If an error occurs, { See also query} Exceptions  Exception If the callback runs immediately and an error occurs in it Since 1.22 Implements Wikimedia\Rdbms\IDatabase. Definition at line 611 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ onTransactionResolution()  Wikimedia\Rdbms\DBConnRef::onTransactionResolution ( callable$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 $fname Caller name Exceptions  DBError If an error occurs, { See also query} Exceptions  Exception If the callback runs immediately and an error occurs in it Since 1.28 Implements Wikimedia\Rdbms\IDatabase. Definition at line 601 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ pendingWriteCallers()  Wikimedia\Rdbms\DBConnRef::pendingWriteCallers ( ) Get the list of method names that did write queries for this transaction. Returns array Since 1.27 Implements Wikimedia\Rdbms\IDatabase. Definition at line 168 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ pendingWriteQueryDuration()  Wikimedia\Rdbms\DBConnRef::pendingWriteQueryDuration ($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 $type IDatabase::ESTIMATE_* constant [default: ESTIMATE_ALL] Returns float|bool Returns false if not transaction is active Since 1.26 Implements Wikimedia\Rdbms\IDatabase. Definition at line 164 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ ping()  Wikimedia\Rdbms\DBConnRef::ping ( &$rtt = null )

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

Parameters
 float | null &$rtt Value to store the estimated RTT [optional] Returns bool Success or failure Implements Wikimedia\Rdbms\IDatabase. Definition at line 672 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ primaryPosWait()  Wikimedia\Rdbms\DBConnRef::primaryPosWait ( DBPrimaryPos$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 $timeout The maximum number of seconds to wait for synchronisation Returns int|null Zero if the replica DB was past that position already, greater than zero if we waited for some period of time, less than zero if it timed out, and null on error Exceptions  DBError If an error occurs, { See also query} Since 1.37 Implements Wikimedia\Rdbms\IDatabase. Definition at line 585 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ query()  Wikimedia\Rdbms\DBConnRef::query ($sql, $fname = __METHOD__,$flags = 0 )

Run an SQL query 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 $sql SQL query string$fname Name of the calling function, for profiling/SHOW PROCESSLIST comment (you can use METHOD or add some extra info) int $flags Bit field of IDatabase::QUERY_* constants. Note that suppression of errors is best handled by try/catch rather than using one of these flags. Returns bool|IResultWrapper True for a successful write query, IResultWrapper object for a successful read query, or false on failure if QUERY_SILENCE_ERRORS is set. Exceptions  DBQueryError If the query is issued, fails, and QUERY_SILENCE_ERRORS is not set. DBExpectedError If the query is not, and cannot, be issued yet (non-DBQueryError) DBError If the query is inherently not allowed (non-DBExpectedError) Implements Wikimedia\Rdbms\IDatabase. Definition at line 282 of file DBConnRef.php. ## ◆ replace()  Wikimedia\Rdbms\DBConnRef::replace ($table, $uniqueKeys,$rows, $fname = __METHOD__ ) Insert row(s) into a table, deleting all conflicting rows beforehand. Note some important implications of the deletion semantics: • If the table has an AUTOINCREMENT column and$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 $table The table name string | string[] | string[][]$uniqueKeys Column 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[] $rows Row(s) to insert, in the form of either: A string-keyed map of (column name => value) defining a new row. Values are treated as literals and quoted appropriately; null is interpreted as NULL. Columns belonging to a key in$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 $fname Calling function name (use METHOD) for logs/profiling Exceptions  DBError If an error occurs, { See also query} Implements Wikimedia\Rdbms\IDatabase. Definition at line 505 of file DBConnRef.php. ## ◆ restoreFlags()  Wikimedia\Rdbms\DBConnRef::restoreFlags ($state = self::RESTORE_PRIOR )

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

Parameters
 string $state IDatabase::RESTORE_* constant. [default: RESTORE_PRIOR] Since 1.28 Implements Wikimedia\Rdbms\IDatabase. Definition at line 184 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ rollback()  Wikimedia\Rdbms\DBConnRef::rollback ($fname = __METHOD__, $flush = self::FLUSHING_ONE ) Rollback a transaction previously started using begin() Only call this from code with outer transaction scope. See https://www.mediawiki.org/wiki/Database_transactions for details. Nesting of transactions is not supported. If a serious unexpected error occurs, throwing an Exception is preferable, using a pre-installed error handler to trigger rollback (in any case, failure to issue COMMIT will cause rollback server-side). Query, connection, and onTransaction* callback errors will be suppressed and logged. Parameters  string$fname Calling function name string $flush Flush flag, set to a situationally valid IDatabase::FLUSHING_* constant to disable warnings about calling rollback when no transaction is in progress. This will silently break any ongoing explicit transaction. Only set the flush flag if you are sure that it is safe to ignore these warnings in your context. Exceptions  DBError If an error occurs, { See also query} Since 1.23 Added$flush parameter

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 656 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ select()

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

Execute a SELECT query constructed using the various parameters provided.

Parameters
 string | array $table Table 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 $vars Field name(s) May be either a field name or an array of field names. The field names can be complete fragments of SQL, for direct inclusion into the SELECT query. If an array is given, field aliases can be specified, for example: [ 'maxrev' => 'MAX(rev_id)' ] This includes an expression with the alias "maxrev" in the query. If an expression is given, care must be taken to ensure that it is DBMS-independent. Untrusted user input must not be passed to this parameter. Parameters  string | array$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:

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):

// $join_conds... 'actor' => [ 'JOIN', 'rev_actor = actor_id' ],  Parameters  string$fname Caller function name string | array $options Query 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_conds Join 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
 DBError If an error occurs, {
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 315 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ 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
 DBConnectionError If databasesAreIndependent() is true and connection change fails DBError On query error or if database changes are disallowed
Deprecated:

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 449 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
 DBConnectionError If databasesAreIndependent() is true and connection change fails DBError On query error, if domain changes are disallowed, or the domain is invalid
Since
1.32

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 455 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.

Parameters
 string | array $table Table name. { See also select} for details. Parameters  string | array$var The 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. {
select} for details.
Parameters
 string | array $cond The condition array. { See also select} for details. Parameters  string$fname The function name of the caller. string | array $options The query options. { See also select} for details. Parameters  string | array$join_conds The query join conditions. {
select} for details.
Returns
mixed|false The value from the field, or false if nothing was found
Exceptions
 DBError If an error occurs, {
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 303 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ 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.

Parameters
 string | array $table Table name. { See also select} for details. Parameters  string$var The field name to select. This must be a valid SQL fragment: do not use unvalidated user input. string | array $cond The condition array. { See also select} for details. Parameters  string$fname The function name of the caller. string | array $options The query options. { See also select} for details. Parameters  string | array$join_conds The query join conditions. {
select} for details.
Returns
array The values from the field in the order they were returned from the DB
Exceptions
 DBError If an error occurs, {
query}
Since
1.25

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 309 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ 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.

Parameters
 string | array $table Table name string | array$vars Field names string | array $conds Conditions string$fname Caller function name string | array $options Query options array | string$join_conds Join conditions
Returns
stdClass|bool
Exceptions
 DBError If an error occurs, {
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 333 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ 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().

Since
1.27 Added $join_conds parameter Parameters  string | string[]$tables Table name(s) string $var Column for which NULL values are not counted [default "*"] array | string$conds Filters on the table string $fname Function name for profiling array$options Options for select array $join_conds Join conditions (since 1.27) Returns int Row count Exceptions  DBError If an error occurs, { See also query} Implements Wikimedia\Rdbms\IDatabase. Definition at line 346 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ selectSQLText()  Wikimedia\Rdbms\DBConnRef::selectSQLText ($table, $vars,$conds = '', $fname = __METHOD__,$options = [], $join_conds = [] ) Take the same arguments as IDatabase::select() and return the SQL it would use. This can be useful for making UNION queries, where the SQL text of each query is needed. In general, however, callers outside of Database classes should just use select(). See also IDatabase::select() Parameters  string | array$table Table name string | array $vars Field names string | array$conds Conditions string $fname Caller function name string | array$options Query options string | array $join_conds Join conditions Returns string SQL query string Implements Wikimedia\Rdbms\IDatabase. Definition at line 322 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ serverIsReadOnly()  Wikimedia\Rdbms\DBConnRef::serverIsReadOnly ( ) Returns bool Whether the DB is marked as read-only server-side Exceptions  DBError If an error occurs, { See also query} Since 1.28 Implements Wikimedia\Rdbms\IDatabase. Definition at line 597 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ setBigSelects()  Wikimedia\Rdbms\DBConnRef::setBigSelects ($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 $value True for allow, false for deny, or "default" to restore the initial value Implements Wikimedia\Rdbms\IDatabase. Definition at line 742 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ setFlag()  Wikimedia\Rdbms\DBConnRef::setFlag ($flag, $remember = self::REMEMBER_NOTHING ) Set a flag for this connection. Parameters  int$flag One of (IDatabase::DBO_DEBUG, IDatabase::DBO_TRX) string $remember IDatabase::REMEMBER_* constant [default: REMEMBER_NOTHING] Implements Wikimedia\Rdbms\IDatabase. Definition at line 176 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ setIndexAliases()  Wikimedia\Rdbms\DBConnRef::setIndexAliases ( array$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[] $aliases Since 1.31 Implements Wikimedia\Rdbms\IDatabase. Definition at line 754 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ setLBInfo()  Wikimedia\Rdbms\DBConnRef::setLBInfo ($nameOrArray, $value = null ) Set the entire array or a particular key of the managing load balancer info array. Keys matching the IDatabase::LB_* constants are also used internally by subclasses Parameters  array | string$nameOrArray The new array or the name of a key to set array | null $value If$nameOrArray is a string, the new key value (null to unset)

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 138 of file DBConnRef.php.

## ◆ setSchemaVars()

 Wikimedia\Rdbms\DBConnRef::setSchemaVars ( $vars ) Set schema variables to be used when streaming commands from SQL files or stdin. Variables appear as SQL comments and are substituted by their corresponding values Parameters  array | null$vars Map of (variable => value) or null to use the defaults

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 698 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ 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 $options Returns void Exceptions  DBError If an error occurs, { See also query} Implements Wikimedia\Rdbms\IDatabase. Definition at line 694 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ setTableAliases()  Wikimedia\Rdbms\DBConnRef::setTableAliases ( array$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[] $aliases Map of (table => (dbname, schema, prefix) map) Since 1.28 Implements Wikimedia\Rdbms\IDatabase. Definition at line 750 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ setTransactionListener()  Wikimedia\Rdbms\DBConnRef::setTransactionListener ($name, callable $callback = null ) Run a callback after each time any transaction commits or rolls back. The callback takes two arguments: • IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_ROLLBACK • This IDatabase object Callbacks must commit any transactions that they begin. Registering a callback here will not affect writesOrCallbacks() pending. Since callbacks from this or onTransactionCommitOrIdle() can start and end transactions, a single call to IDatabase::commit might trigger multiple runs of the listener callbacks. Parameters  string$name Callback name callable | null $callback Use null to unset a listener Since 1.28 Implements Wikimedia\Rdbms\IDatabase. Definition at line 620 of file DBConnRef.php. References Wikimedia\Rdbms\DBConnRef\__call(). ## ◆ startAtomic()  Wikimedia\Rdbms\DBConnRef::startAtomic ($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 $fname string$cancelable Pass self::ATOMIC_CANCELABLE to use a savepoint and enable self::cancelAtomic() for this section.
Returns
AtomicSectionIdentifier section ID token
Exceptions
 DBError If an error occurs, {
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 624 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ strreplace()

 Wikimedia\Rdbms\DBConnRef::strreplace ( $orig,$old, $new ) Returns a SQL expression for simple string replacement (e.g. REPLACE() in mysql) Parameters  string$orig Column to modify string $old Column to seek string$new Column to replace with
Returns
string

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 561 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ tableExists()

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

Query whether a given table exists.

Parameters
 string $table string$fname
Returns
bool
Exceptions
 DBError If an error occurs, {
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 368 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ tablePrefix()

 Wikimedia\Rdbms\DBConnRef::tablePrefix ( $prefix = null ) Get/set the table prefix. Parameters  string | null$prefix The table prefix to set, or omitted to leave it unchanged
Returns
string The previous table prefix

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 108 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\IDatabase.

Definition at line 664 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ 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\IDatabase.

Definition at line 668 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ 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 96 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 100 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ unionConditionPermutations()

 Wikimedia\Rdbms\DBConnRef::unionConditionPermutations ( $table,$vars, array $permute_conds,$extra_conds = '', $fname = __METHOD__,$options = [], $join_conds = [] ) Construct a UNION query for permutations of conditions. Databases sometimes have trouble with queries that have multiple values for multiple condition parameters combined with limits and ordering. This method constructs queries for the Cartesian product of the conditions and unions them all together. See also IDatabase::select() Parameters  string | array$table Table name string | array $vars Field names array$permute_conds Conditions for the Cartesian product. Keys are field names, values are arrays of the possible values for that field. string | array $extra_conds Additional conditions to include in the query. string$fname Caller function name string | array $options Query options. In addition to the options recognized by IDatabase::select(), the following may be used: NOTALL: Set to use UNION instead of UNION ALL. INNER ORDER BY: If specified and supported, subqueries will use this instead of ORDER BY. string | array$join_conds Join conditions
Returns
string SQL query string.
Since
1.30

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 550 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ 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 $sqls SQL statements to combine bool$all Either IDatabase::UNION_ALL or IDatabase::UNION_DISTINCT
Returns
string SQL fragment

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 546 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ unionSupportsOrderAndLimit()

 Wikimedia\Rdbms\DBConnRef::unionSupportsOrderAndLimit ( )

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

Returns
bool

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 542 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ unlock()

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

Release a lock.

Named locks are not related to transactions

Parameters
 string $lockName Name of lock to release string$method Name of the calling method
Returns
bool Success
Exceptions
 DBError If an error occurs, {
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 714 of file DBConnRef.php.

## ◆ update()

 Wikimedia\Rdbms\DBConnRef::update ( $table,$set, $conds,$fname = __METHOD__, $options = [] ) Update all rows in a table that match a given condition. Parameters  string$table Table name array $set Combination map/list where each string-keyed entry maps a column to a literal assigned value and each integer-keyed value is a SQL expression in the format of a column assignment within UPDATE...SET. The (column => value) entries are convenient due to automatic value quoting and conversion of null to NULL. The SQL assignment format is useful for updates like "column = column + X". All assignments have no defined execution order, so they should not depend on each other. Do not modify AUTOINCREMENT or UUID columns in assignments. array | string$conds Condition 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 explicitely in order to update all rows. string $fname Calling function name (use METHOD) for logs/profiling string | array$options Combination 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
 DBError If an error occurs, {
query}

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 378 of file DBConnRef.php.

## ◆ upsert()

 Wikimedia\Rdbms\DBConnRef::upsert ( $table, array$rows, $uniqueKeys, array$set, $fname = __METHOD__ ) Upsert the given row(s) into a table. This updates any existing rows that conflict with the provided rows and inserts any of the provided rows that do not conflict with existing rows. Conflicts are determined by the provided unique indexes. Parameters  string$table Table name array | array[] $rows Row(s) to insert, in the form of either: A string-keyed map of (column name => value) defining a new row. Values are treated as literals and quoted appropriately; null is interpreted as NULL. Columns belonging to a key in$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[][] $uniqueKeys Column name or non-empty list of column name lists that define all applicable unique keys on the table. There must only be one such key. Each unique key on the table is "applicable" unless either: It involves an AUTOINCREMENT column for which no values are assigned in$rows It involves a UUID column for which newly generated UUIDs are assigned in $rows Passing string[] to$uniqueKeys is deprecated. array $set Combination map/list where each string-keyed entry maps a column to a literal assigned value and each integer-keyed value is a SQL assignment expression of the form " = ". The (column => value) entries are convenient due to automatic value quoting and conversion of null to NULL. The SQL assignment entries are useful for updates like "column = column + X". All of the assignments have no defined execution order, so callers should make sure that they not depend on each other. Do not modify AUTOINCREMENT or UUID columns in assignments, even if they are just "secondary" unique keys. string$fname Calling function name (use METHOD) for logs/profiling
Returns
bool Return true if no exception was thrown (deprecated since 1.33)
Exceptions
 DBError If an error occurs, {
query}
Since
1.22

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 511 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 573 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

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 565 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ 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 581 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ 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 569 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

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

Returns
bool

Implements Wikimedia\Rdbms\IDatabase.

Definition at line 577 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ 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 160 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 156 of file DBConnRef.php.

References Wikimedia\Rdbms\DBConnRef\__call().

## ◆ $conn  Database null Wikimedia\Rdbms\DBConnRef::$conn
private

Live connection handle.

Definition at line 34 of file DBConnRef.php.

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

## ◆ $lb  ILoadBalancer Wikimedia\Rdbms\DBConnRef::$lb
private

Definition at line 32 of file DBConnRef.php.

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

## ◆ $params  array Wikimedia\Rdbms\DBConnRef::$params
private

N-tuple of (server index, group, DatabaseDomain|string)

Definition at line 36 of file DBConnRef.php.

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

## ◆ $role  int Wikimedia\Rdbms\DBConnRef::$role
private

One of DB_PRIMARY/DB_REPLICA.

Definition at line 38 of file DBConnRef.php.

## ◆ FLD_DOMAIN

 const Wikimedia\Rdbms\DBConnRef::FLD_DOMAIN = 2
private

Definition at line 42 of file DBConnRef.php.

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

## ◆ FLD_FLAGS

 const Wikimedia\Rdbms\DBConnRef::FLD_FLAGS = 3
private

Definition at line 43 of file DBConnRef.php.

## ◆ FLD_GROUP

 const Wikimedia\Rdbms\DBConnRef::FLD_GROUP = 1
private

Definition at line 41 of file DBConnRef.php.

## ◆ FLD_INDEX

 const Wikimedia\Rdbms\DBConnRef::FLD_INDEX = 0
private

Definition at line 40 of file DBConnRef.php.

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

The documentation for this class was generated from the following file:
LIST_OR
const LIST_OR
Definition: Defines.php:46
LIST_AND
const LIST_AND
Definition: Defines.php:43
Wikimedia\Rdbms\DBConnRef\$conn Database null$conn
Live connection handle.
Definition: DBConnRef.php:34
DB_REPLICA
const DB_REPLICA
Definition: defines.php:25
$path$path
Definition: NoLocalSettings.php:25
Wikimedia\Rdbms\Database\select
select( $table,$vars, $conds='',$fname=__METHOD__, $options=[],$join_conds=[])
Execute a SELECT query constructed using the various parameters provided.
Definition: Database.php:1997
$type$type
Definition: testCompression.php:52