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BatchRowIterator Class Reference

Allows iterating a large number of rows in batches transparently. More...

Inherits RecursiveIterator.

Collaboration diagram for BatchRowIterator:

Public Member Functions

 __construct (IReadableDatabase $db, $sqb, $primaryKey, $batchSize)
 
 addConditions (array $conditions)
 
 addJoinConditions (array $conditions)
 
 addOptions (array $options)
 
 current ()
 
 extractPrimaryKeys ( $row)
 Extracts the primary key(s) from a database row.
 
 getChildren ()
 
 hasChildren ()
 
 key ()
 
 next ()
 Fetch the next set of rows from the database.
 
 rewind ()
 Reset the iterator to the beginning of the table.
 
 setCaller ( $caller)
 Use ->setCaller( METHOD ) to indicate which code is using this class.
 
 setFetchColumns (array $columns)
 
 valid ()
 

Public Attributes

SelectQueryBuilder $sqb
 Underlying database query builder, may be mutated before iteration begins.
 

Protected Member Functions

 buildConditions ()
 Uses the primary key list and the maximal result row from the previous iteration to build an SQL condition sufficient for selecting the next page of results.
 

Protected Attributes

int $batchSize
 The number of rows to fetch per iteration.
 
IReadableDatabase $db
 
array $primaryKey
 The name of the primary key(s)
 

Detailed Description

Allows iterating a large number of rows in batches transparently.

By default when iterated over returns the full query result as an array of rows. Can be wrapped in RecursiveIteratorIterator to collapse those arrays into a single stream of rows queried in batches.

Stability: newable

Definition at line 34 of file BatchRowIterator.php.

Constructor & Destructor Documentation

◆ __construct()

BatchRowIterator::__construct ( IReadableDatabase $db,
$sqb,
$primaryKey,
$batchSize )
Stability: stable
to call
Parameters
IReadableDatabase$db
SelectQueryBuilder | string | array$sqbThe query to split into batches (or table name/names)
string | array$primaryKeyThe name or names of the primary key columns
int$batchSizeThe number of rows to fetch per iteration

Definition at line 71 of file BatchRowIterator.php.

References $batchSize, $db, $primaryKey, $sqb, and Wikimedia\Rdbms\IReadableDatabase\newSelectQueryBuilder().

Member Function Documentation

◆ addConditions()

BatchRowIterator::addConditions ( array $conditions)
Deprecated
since 1.44 Use the SelectQueryBuilder object directly
Parameters
array$conditionsQuery conditions suitable for use with IDatabase::select

Definition at line 94 of file BatchRowIterator.php.

◆ addJoinConditions()

BatchRowIterator::addJoinConditions ( array $conditions)
Deprecated
since 1.44 Use the SelectQueryBuilder object directly
Parameters
array$conditionsQuery join conditions suitable for use with IDatabase::select

Definition at line 112 of file BatchRowIterator.php.

◆ addOptions()

BatchRowIterator::addOptions ( array $options)
Deprecated
since 1.44 Use the SelectQueryBuilder object directly
Parameters
array$optionsQuery options suitable for use with IDatabase::select

Definition at line 103 of file BatchRowIterator.php.

◆ buildConditions()

BatchRowIterator::buildConditions ( )
protected

Uses the primary key list and the maximal result row from the previous iteration to build an SQL condition sufficient for selecting the next page of results.

Returns
array The SQL conditions necessary to select the next set of rows in the batched query

Definition at line 230 of file BatchRowIterator.php.

◆ current()

BatchRowIterator::current ( )
Returns
array The most recently fetched set of rows from the database

Definition at line 167 of file BatchRowIterator.php.

◆ extractPrimaryKeys()

BatchRowIterator::extractPrimaryKeys ( $row)

Extracts the primary key(s) from a database row.

Parameters
stdClass$rowAn individual database row from this iterator
Returns
array Map of primary key column to value within the row

Definition at line 155 of file BatchRowIterator.php.

◆ getChildren()

BatchRowIterator::getChildren ( )

Definition at line 201 of file BatchRowIterator.php.

◆ hasChildren()

BatchRowIterator::hasChildren ( )
Returns
bool True when this result set has rows

Definition at line 197 of file BatchRowIterator.php.

◆ key()

BatchRowIterator::key ( )
Returns
int 0-indexed count of the page number fetched

Definition at line 174 of file BatchRowIterator.php.

◆ next()

BatchRowIterator::next ( )

Fetch the next set of rows from the database.

Definition at line 208 of file BatchRowIterator.php.

◆ rewind()

BatchRowIterator::rewind ( )

Reset the iterator to the beginning of the table.

Definition at line 181 of file BatchRowIterator.php.

◆ setCaller()

BatchRowIterator::setCaller ( $caller)

Use ->setCaller( METHOD ) to indicate which code is using this class.

Only used in debugging output.

Since
1.36
Deprecated
since 1.44 Use the SelectQueryBuilder object directly
Parameters
string$caller
Returns
self

Definition at line 143 of file BatchRowIterator.php.

◆ setFetchColumns()

BatchRowIterator::setFetchColumns ( array $columns)
Deprecated
since 1.44 Use the SelectQueryBuilder object directly
Parameters
array$columnsList of column names to select from the table suitable for use with IDatabase::select()

Definition at line 121 of file BatchRowIterator.php.

◆ valid()

BatchRowIterator::valid ( )
Returns
bool True when the iterator is in a valid state

Definition at line 190 of file BatchRowIterator.php.

Member Data Documentation

◆ $batchSize

int BatchRowIterator::$batchSize
protected

The number of rows to fetch per iteration.

Definition at line 46 of file BatchRowIterator.php.

Referenced by __construct().

◆ $db

IReadableDatabase BatchRowIterator::$db
protected

Definition at line 36 of file BatchRowIterator.php.

Referenced by __construct().

◆ $primaryKey

array BatchRowIterator::$primaryKey
protected

The name of the primary key(s)

Definition at line 41 of file BatchRowIterator.php.

Referenced by __construct().

◆ $sqb

SelectQueryBuilder BatchRowIterator::$sqb

Underlying database query builder, may be mutated before iteration begins.

Definition at line 61 of file BatchRowIterator.php.

Referenced by __construct().


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