There is also a way to specifie the default fetch mode :
$connection = new PDO($connection_string);
(PHP 5 >= 5.1.0, PECL pdo >= 0.1.0)
PDO::setAttribute — Set an attribute
Sets an attribute on the database handle. Some of the available generic attributes are listed below; some drivers may make use of additional driver specific attributes.
PDO::ATTR_CASE: Force column names to a specific case.
PDO::CASE_LOWER: Force column names to lower case.
PDO::CASE_NATURAL: Leave column names as returned by the database driver.
PDO::CASE_UPPER: Force column names to upper case.
PDO::ATTR_ERRMODE: Error reporting.
PDO::ATTR_ORACLE_NULLS (available with all drivers, not just Oracle): Conversion of NULL and empty strings.
PDO::NULL_NATURAL: No conversion.
PDO::NULL_EMPTY_STRING: Empty string is converted to
PDO::NULL_TO_STRING: NULL is converted to an empty string.
PDO::ATTR_STRINGIFY_FETCHES: Convert numeric values to strings when fetching. Requires bool.
PDO::ATTR_STATEMENT_CLASS: Set user-supplied statement class derived from PDOStatement. Cannot be used with persistent PDO instances. Requires array(string classname, array(mixed constructor_args)).
PDO::ATTR_TIMEOUT: Specifies the timeout duration in seconds. Not all drivers support this option, and it's meaning may differ from driver to driver. For example, sqlite will wait for up to this time value before giving up on obtaining an writable lock, but other drivers may interpret this as a connect or a read timeout interval. Requires int.
PDO::ATTR_AUTOCOMMIT (available in OCI, Firebird and MySQL): Whether to autocommit every single statement.
PDO::ATTR_EMULATE_PREPARES Enables or disables emulation of prepared statements. Some drivers do not support native prepared statements or have limited support for them. Use this setting to force PDO to either always emulate prepared statements (if
TRUE), or to try to use native prepared statements (if
FALSE). It will always fall back to emulating the prepared statement if the driver cannot successfully prepare the current query. Requires bool.
PDO::MYSQL_ATTR_USE_BUFFERED_QUERY (available in MySQL): Use buffered queries.
PDO::ATTR_DEFAULT_FETCH_MODE: Set default fetch mode. Description of modes is available in PDOStatement::fetch() documentation.
TRUE in caso di successo,
FALSE in caso di fallimento.
It is worth noting that not all attributes may be settable via setAttribute(). For example, PDO::MYSQL_ATTR_MAX_BUFFER_SIZE is only settable in PDO::__construct(). You must pass PDO::MYSQL_ATTR_MAX_BUFFER_SIZE as part of the optional 4th parameter to the constructor. This is detailed in http://bugs.php.net/bug.php?id=38015
Calling this function with PDO::MYSQL_ATTR_USE_BUFFERED_QUERY will seem to work, but it DOES NOT.
Instead, set it in the options array when instantiating the PDO connection.
$con = new PDO("mysql:dbname=dbname;host=some.ip", "user", "pass", array(
PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => true,
Because no examples are provided, and to alleviate any confusion as a result, the setAttribute() method is invoked like so:
So, if I wanted to ensure that the column names returned from a query were returned in the case the database driver returned them (rather than having them returned in all upper case [as is the default on some of the PDO extensions]), I would do the following:
// Create a new database connection.
$dbConnection = new PDO($dsn, $user, $pass);
// Set the case in which to return column_names.
Hope this helps some of you who learn by example (as is the case with me).
if you are wondering about a size-bound (1 MB) on blob and text fields after upgrading to PHP5.1.4. You might try to increase this limit by using the setAttribute() method.
This will fail. Instead use the options array when instantiating the pdo:
$pdo = new PDO ("connection_settings", "user", "pass", array
This should fix the problem and increase the limit to 50 MB.