class StatementWrapperIterator
Same name in other branches
- 11.x core/lib/Drupal/Core/Database/StatementWrapperIterator.php \Drupal\Core\Database\StatementWrapperIterator
StatementInterface iterator implementation.
This class is meant to be generic enough for any type of database clients, even if all Drupal core database drivers currently use PDO clients. We implement \Iterator instead of \IteratorAggregate to allow iteration to be kept in sync with the underlying database resultset cursor. PDO is not able to execute a database operation while a cursor is open on the result of an earlier select query, so Drupal by default uses buffered queries setting \PDO::MYSQL_ATTR_USE_BUFFERED_QUERY to TRUE on the connection. This forces the query to return all the results in a buffer local to the client library, potentially leading to memory issues in case of large datasets being returned by a query. Other database clients, however, could allow multithread queries, or developers could disable buffered queries in PDO: in that case, this class prevents the resultset to be entirely fetched in PHP memory (that an \IteratorAggregate implementation would force) and therefore optimize memory usage while iterating the resultset.
Hierarchy
- class \Drupal\Core\Database\StatementWrapperIterator implements \Drupal\Core\Database\Iterator, \Drupal\Core\Database\StatementInterface uses \Drupal\Core\Database\StatementIteratorTrait, \Drupal\Core\Database\FetchModeTrait
Expanded class hierarchy of StatementWrapperIterator
2 files declare their use of StatementWrapperIterator
- Connection.php in core/
modules/ mysql/ src/ Driver/ Database/ mysql/ Connection.php - Connection.php in core/
modules/ pgsql/ src/ Driver/ Database/ pgsql/ Connection.php
File
-
core/
lib/ Drupal/ Core/ Database/ StatementWrapperIterator.php, line 29
Namespace
Drupal\Core\DatabaseView source
class StatementWrapperIterator implements \Iterator, StatementInterface {
use StatementIteratorTrait;
use FetchModeTrait;
/**
* The client database Statement object.
*
* For a \PDO client connection, this will be a \PDOStatement object.
*/
protected object $clientStatement;
/**
* Constructs a StatementWrapperIterator object.
*
* @param \Drupal\Core\Database\Connection $connection
* Drupal database connection object.
* @param object $clientConnection
* Client database connection object, for example \PDO.
* @param string $query
* The SQL query string.
* @param array $options
* Array of query options.
* @param bool $rowCountEnabled
* (optional) Enables counting the rows matched. Defaults to FALSE.
*/
public function __construct(Connection $connection, object $clientConnection, string $query, array $options, bool $rowCountEnabled = FALSE) {
$this->clientStatement = $clientConnection->prepare($query, $options);
$this->setFetchMode(\PDO::FETCH_OBJ);
}
/**
* Returns the client-level database statement object.
*
* This method should normally be used only within database driver code.
*
* @return object
* The client-level database statement, for example \PDOStatement.
*/
public function getClientStatement() : object {
return $this->clientStatement;
}
/**
* {@inheritdoc}
*/
public function getConnectionTarget() : string {
return $this->connection
->getTarget();
}
/**
* {@inheritdoc}
*/
public function execute($args = [], $options = []) {
if (isset($options['fetch'])) {
if (is_string($options['fetch'])) {
// \PDO::FETCH_PROPS_LATE tells __construct() to run before properties
// are added to the object.
$this->setFetchMode(\PDO::FETCH_CLASS | \PDO::FETCH_PROPS_LATE, $options['fetch']);
}
else {
$this->setFetchMode($options['fetch']);
}
}
if ($this->connection
->isEventEnabled(StatementExecutionStartEvent::class)) {
$startEvent = new StatementExecutionStartEvent(spl_object_id($this), $this->connection
->getKey(), $this->connection
->getTarget(), $this->getQueryString(), $args ?? [], $this->connection
->findCallerFromDebugBacktrace());
$this->connection
->dispatchEvent($startEvent);
}
try {
$return = $this->clientStatement
->execute($args);
$this->markResultsetIterable($return);
} catch (\Exception $e) {
if (isset($startEvent) && $this->connection
->isEventEnabled(StatementExecutionFailureEvent::class)) {
$this->connection
->dispatchEvent(new StatementExecutionFailureEvent($startEvent->statementObjectId, $startEvent->key, $startEvent->target, $startEvent->queryString, $startEvent->args, $startEvent->caller, $startEvent->time, get_class($e), $e->getCode(), $e->getMessage()));
}
throw $e;
}
if (isset($startEvent) && $this->connection
->isEventEnabled(StatementExecutionEndEvent::class)) {
$this->connection
->dispatchEvent(new StatementExecutionEndEvent($startEvent->statementObjectId, $startEvent->key, $startEvent->target, $startEvent->queryString, $startEvent->args, $startEvent->caller, $startEvent->time));
}
return $return;
}
/**
* {@inheritdoc}
*/
public function getQueryString() {
return $this->clientStatement->queryString;
}
/**
* {@inheritdoc}
*/
public function fetchCol($index = 0) {
return $this->fetchAll(\PDO::FETCH_COLUMN, $index);
}
/**
* {@inheritdoc}
*/
public function fetchAllAssoc($key, $fetch = NULL) {
if (isset($fetch)) {
if (is_string($fetch)) {
$this->setFetchMode(\PDO::FETCH_CLASS, $fetch);
}
else {
$this->setFetchMode($fetch);
}
}
// Return early if the statement was already fully traversed.
if (!$this->isResultsetIterable) {
return [];
}
// Once the while loop is completed, the resultset is marked so not to
// allow more fetching.
$return = [];
while ($record = $this->fetch()) {
$recordKey = is_object($record) ? $record->{$key} : $record[$key];
$return[$recordKey] = $record;
}
return $return;
}
/**
* {@inheritdoc}
*/
public function fetchAllKeyed($key_index = 0, $value_index = 1) {
$this->setFetchMode(\PDO::FETCH_NUM);
// Return early if the statement was already fully traversed.
if (!$this->isResultsetIterable) {
return [];
}
// Once the while loop is completed, the resultset is marked so not to
// allow more fetching.
$return = [];
while ($record = $this->fetch()) {
$return[$record[$key_index]] = $record[$value_index];
}
return $return;
}
/**
* {@inheritdoc}
*/
public function fetchField($index = 0) {
// Call \PDOStatement::fetchColumn to fetch the field.
$column = $this->clientStatement
->fetchColumn($index);
if ($column === FALSE) {
$this->markResultsetFetchingComplete();
return FALSE;
}
$this->setResultsetCurrentRow($column);
return $column;
}
/**
* {@inheritdoc}
*/
public function fetchAssoc() {
return $this->fetch(\PDO::FETCH_ASSOC);
}
/**
* {@inheritdoc}
*/
public function fetchObject(?string $class_name = NULL, array $constructor_arguments = []) {
if ($class_name) {
$row = $this->clientStatement
->fetchObject($class_name, $constructor_arguments);
}
else {
$row = $this->clientStatement
->fetchObject();
}
if ($row === FALSE) {
$this->markResultsetFetchingComplete();
return FALSE;
}
$this->setResultsetCurrentRow($row);
return $row;
}
/**
* {@inheritdoc}
*/
public function rowCount() {
// SELECT query should not use the method.
if ($this->rowCountEnabled) {
return $this->clientStatement
->rowCount();
}
else {
throw new RowCountException();
}
}
/**
* {@inheritdoc}
*/
public function setFetchMode($mode, $a1 = NULL, $a2 = []) {
if (!in_array($mode, $this->supportedFetchModes)) {
@trigger_error('Fetch mode ' . ($this->fetchModeLiterals[$mode] ?? $mode) . ' is deprecated in drupal:10.2.0 and is removed from drupal:11.0.0. Use supported modes only. See https://www.drupal.org/node/3377999', E_USER_DEPRECATED);
}
// Call \PDOStatement::setFetchMode to set fetch mode.
// \PDOStatement is picky about the number of arguments in some cases so we
// need to be pass the exact number of arguments we where given.
return match (func_num_args()) { 1 => $this->clientStatement
->setFetchMode($mode),
2 => $this->clientStatement
->setFetchMode($mode, $a1),
default => $this->clientStatement
->setFetchMode($mode, $a1, $a2),
};
}
/**
* {@inheritdoc}
*/
public function fetch($mode = NULL, $cursor_orientation = NULL, $cursor_offset = NULL) {
if (isset($mode) && !in_array($mode, $this->supportedFetchModes)) {
@trigger_error('Fetch mode ' . ($this->fetchModeLiterals[$mode] ?? $mode) . ' is deprecated in drupal:10.2.0 and is removed from drupal:11.0.0. Use supported modes only. See https://www.drupal.org/node/3377999', E_USER_DEPRECATED);
}
// Call \PDOStatement::fetchAll to fetch all rows.
// \PDOStatement is picky about the number of arguments in some cases so we
// need to pass the exact number of arguments we were given.
$row = match (func_num_args()) { 0 => $this->clientStatement
->fetch(),
1 => $this->clientStatement
->fetch($mode),
2 => $this->clientStatement
->fetch($mode, $cursor_orientation),
default => $this->clientStatement
->fetch($mode, $cursor_orientation, $cursor_offset),
};
if ($row === FALSE) {
$this->markResultsetFetchingComplete();
return FALSE;
}
$this->setResultsetCurrentRow($row);
return $row;
}
/**
* {@inheritdoc}
*/
public function fetchAll($mode = NULL, $column_index = NULL, $constructor_arguments = NULL) {
if (isset($mode) && !in_array($mode, $this->supportedFetchModes)) {
@trigger_error('Fetch mode ' . ($this->fetchModeLiterals[$mode] ?? $mode) . ' is deprecated in drupal:10.2.0 and is removed from drupal:11.0.0. Use supported modes only. See https://www.drupal.org/node/3377999', E_USER_DEPRECATED);
}
// Call \PDOStatement::fetchAll to fetch all rows.
// \PDOStatement is picky about the number of arguments in some cases so we
// need to be pass the exact number of arguments we where given.
$return = match (func_num_args()) { 0 => $this->clientStatement
->fetchAll(),
1 => $this->clientStatement
->fetchAll($mode),
2 => $this->clientStatement
->fetchAll($mode, $column_index),
default => $this->clientStatement
->fetchAll($mode, $column_index, $constructor_arguments),
};
$this->markResultsetFetchingComplete();
return $return;
}
}
Members
Title Sort descending | Deprecated | Modifiers | Object type | Summary | Overriden Title |
---|---|---|---|---|---|
FetchModeTrait::$fetchModeLiterals | protected | property | Map FETCH_* modes to their literal for inclusion in messages. | ||
FetchModeTrait::$supportedFetchModes | protected | property | The fetch modes supported. | ||
FetchModeTrait::assocIntoObject | Deprecated | protected | function | Fills an object with data from a FETCH_ASSOC row. | |
FetchModeTrait::assocToBoth | Deprecated | protected | function | Converts a row of data in FETCH_ASSOC format to FETCH_BOTH. | |
FetchModeTrait::assocToClass | protected | function | Converts a row of data in FETCH_ASSOC format to FETCH_CLASS. | ||
FetchModeTrait::assocToClassType | Deprecated | protected | function | Converts a row of data to FETCH_CLASS | FETCH_CLASSTYPE. | |
FetchModeTrait::assocToColumn | protected | function | Converts a row of data in FETCH_ASSOC format to FETCH_COLUMN. | ||
FetchModeTrait::assocToNum | protected | function | Converts a row of data in FETCH_ASSOC format to FETCH_NUM. | ||
FetchModeTrait::assocToObj | protected | function | Converts a row of data in FETCH_ASSOC format to FETCH_OBJ. | ||
StatementIteratorTrait::$isResultsetIterable | private | property | Traces if rows can be fetched from the resultset. | ||
StatementIteratorTrait::$resultsetKey | private | property | The key of the current row. | ||
StatementIteratorTrait::$resultsetRow | private | property | The current row, retrieved in the current fetch format. | ||
StatementIteratorTrait::current | public | function | Returns the current element. | ||
StatementIteratorTrait::getResultsetCurrentRowIndex | protected | function | Returns the row index of the current element in the resultset. | ||
StatementIteratorTrait::key | public | function | Returns the key of the current element. | ||
StatementIteratorTrait::markResultsetFetchingComplete | protected | function | Informs the iterator that no more rows can be fetched from the resultset. | ||
StatementIteratorTrait::markResultsetIterable | protected | function | Informs the iterator whether rows can be fetched from the resultset. | ||
StatementIteratorTrait::next | public | function | Moves the current position to the next element. | ||
StatementIteratorTrait::rewind | public | function | Rewinds back to the first element of the Iterator. | ||
StatementIteratorTrait::setResultsetCurrentRow | protected | function | Sets the current resultset row for the iterator, and increments the key. | ||
StatementIteratorTrait::valid | public | function | Checks if current position is valid. | ||
StatementWrapperIterator::$clientStatement | protected | property | The client database Statement object. | ||
StatementWrapperIterator::execute | public | function | Executes a prepared statement. | Overrides StatementInterface::execute | |
StatementWrapperIterator::fetch | public | function | Fetches the next row from a result set. | Overrides StatementInterface::fetch | |
StatementWrapperIterator::fetchAll | public | function | Returns an array containing all of the result set rows. | Overrides StatementInterface::fetchAll | |
StatementWrapperIterator::fetchAllAssoc | public | function | Returns the result set as an associative array keyed by the given field. | Overrides StatementInterface::fetchAllAssoc | |
StatementWrapperIterator::fetchAllKeyed | public | function | Returns the entire result set as a single associative array. | Overrides StatementInterface::fetchAllKeyed | |
StatementWrapperIterator::fetchAssoc | public | function | Fetches the next row and returns it as an associative array. | Overrides StatementInterface::fetchAssoc | |
StatementWrapperIterator::fetchCol | public | function | Returns an entire single column of a result set as an indexed array. | Overrides StatementInterface::fetchCol | |
StatementWrapperIterator::fetchField | public | function | Returns a single field from the next record of a result set. | Overrides StatementInterface::fetchField | |
StatementWrapperIterator::fetchObject | public | function | Fetches the next row and returns it as an object. | Overrides StatementInterface::fetchObject | |
StatementWrapperIterator::getClientStatement | public | function | Returns the client-level database statement object. | ||
StatementWrapperIterator::getConnectionTarget | public | function | Returns the target connection this statement is associated with. | Overrides StatementInterface::getConnectionTarget | |
StatementWrapperIterator::getQueryString | public | function | Gets the query string of this statement. | Overrides StatementInterface::getQueryString | |
StatementWrapperIterator::rowCount | public | function | Returns the number of rows matched by the last SQL statement. | Overrides StatementInterface::rowCount | |
StatementWrapperIterator::setFetchMode | public | function | Sets the default fetch mode for this statement. | Overrides StatementInterface::setFetchMode | |
StatementWrapperIterator::__construct | public | function | Constructs a StatementWrapperIterator object. |
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