Result¶
A Result object of type \Doctrine\DBAL\Result is returned by
QueryBuilder->executeQuery() for ->select() and ->count()
query types and by Connection->select() and Connection->count() calls.
The object represents a query result set and comes with methods to fetch single rows
with ->fetchAssociative() or to fetch all rows as an array with
->fetchAllAssociative().
In opposite to the Statement formerly returned by the ->execute(),
it cannot also be used to execute a single prepared statement with different
values multiple times.
Warning
The return type of single field values is NOT type safe! If selecting a value from a field that is
defined as int, the Statement result may very well return that as PHP string. This is
true for other database column types like FLOAT, DOUBLE and others.
This is an issue with the database drivers used below, it may happen that MySQL returns an integer
value for an int field, while others may return a string.
In general, the application must take care of an according type cast on their own to reach maximum
DBMS compatibility.
fetchAssociative()¶
Fetch next row from the result. Usually used in while() loops.
This is the recommended way of accessing the result in most use cases.
Typical example:
// use TYPO3\CMS\Core\Utility\GeneralUtility;
// use TYPO3\CMS\Core\Database\ConnectionPool;
// Fetch all records from tt_content on page 42
$queryBuilder = GeneralUtility::makeInstance(ConnectionPool::class)->getQueryBuilderForTable('tt_content');
$result = $queryBuilder
->select('uid', 'bodytext')
->from('tt_content')
->where($queryBuilder->expr()->eq('pid', $queryBuilder->createNamedParameter(42, \PDO::PARAM_INT)))
->executeQuery();
while ($row = $result->fetchAssociative()) {
// Do something useful with that single $row
}
->fetchAssociative() returns an array reflecting one result row,
containing field, value pairs, at one call, retrieving the next row
with the next call. Returns false when no more rows can be found.
fetchAllAssociative()¶
Returns an array containing all of the result set rows by implementing the same while loop as above internally. Using that method saves some precious code characters but is more memory intensive if the result set is large with lots of rows and lot of data since big arrays are carried around in PHP:
// use TYPO3\CMS\Core\Utility\GeneralUtility;
// use TYPO3\CMS\Core\Database\ConnectionPool;
// Fetch all records from tt_content on page 42
$queryBuilder = GeneralUtility::makeInstance(ConnectionPool::class)->getQueryBuilderForTable('tt_content');
$rows = $queryBuilder
->select('uid', 'bodytext')
->from('tt_content')
->where($queryBuilder->expr()->eq('pid', $queryBuilder->createNamedParameter(42, \PDO::PARAM_INT)))
->executeQuery()
->fetchAllAssociative();
fetchOne()¶
Returns a single column from the next row of a result set, other columns from that result row are discarded.
This method is especially handy for QueryBuilder->count() queries.
The Connection->count() implementation does exactly that to return the
number of rows directly:
// use TYPO3\CMS\Core\Utility\GeneralUtility;
// use TYPO3\CMS\Core\Database\ConnectionPool;
// Get the number of tt_content records on pid 42 into variable $numberOfRecords
$queryBuilder = GeneralUtility::makeInstance(ConnectionPool::class)->getQueryBuilderForTable('tt_content');
$numberOfRecords = $queryBuilder
->count('uid')
->from('tt_content')
->where($queryBuilder->expr()->eq('pid', $queryBuilder->createNamedParameter(42, \PDO::PARAM_INT)))
->executeQuery()
->fetchOne();
rowCount()¶
Returns the number of rows affected by the last execution of this statement. Use that method
instead of counting the number of records in a ->fetchAssociative() loop manually.
Warning
->rowCount() works well with DELETE, UPDATE and INSERT queries. However, it does NOT
return a valid number for SELECT queries on some DBMS. Never use ->rowCount() on SELECT
queries. This may work with MySOL, but fails with other databases like SQLite.
Re-use Prepared Statement()¶
Doctrine usually prepares a statement first, and then executes it with given parameters. Implementing prepared statements depends on the given driver. A driver not properly implementing prepared statements fall back to a direct execution of given query.
There is an API to make real use of prepared statements that becomes handy if
the same query is executed with different arguments over and over again. The
example below prepares a statement to the pages table
and executes it twice with different arguments
The following code example is probably outdated:
// use TYPO3\CMS\Core\Utility\GeneralUtility;
// use TYPO3\CMS\Core\Database\ConnectionPool;
$connection = GeneralUtility::makeInstance(ConnectionPool::class)->getConnectionForTable('pages');
$queryBuilder = $connection->createQueryBuilder();
$queryBuilder->getRestrictions()->removeAll();
$sqlStatement = $queryBuilder->select('uid')
->from('pages')
->where($queryBuilder->expr()->eq('uid', $queryBuilder->createPositionalParameter(0, \PDO::PARAM_INT)))
->getSQL();
$statement = $connection->executeQuery($sqlStatement, [ 24 ]);
$result1 = $statement->fetchAssociative();
$statement->closeCursor(); // free the resources for this result
$statement->bindValue(1, 25);
$statement->executeQuery();
$result2 = $statement->fetchAssociative();
$statement->closeCursor(); // free the resources for this result
Looking at a mysql debug log:
Prepare SELECT `uid` FROM `pages` WHERE `uid` = ?
Execute SELECT `uid` FROM `pages` WHERE `uid` = '24'
Execute SELECT `uid` FROM `pages` WHERE `uid` = '25'
The log shows one statement preparation with two executions.