Errors and error handling

PDO offers you a choice of 3 different error handling strategies, to fit your style of application development.

PDO standardizes on using SQL-92 SQLSTATE error code strings; individual PDO drivers are responsible for mapping their native codes to the appropriate SQLSTATE codes. The PDO::errorCode() method returns a single SQLSTATE code. If you need more specific information about an error, PDO also offers an PDO::errorInfo() method which returns an array containing the SQLSTATE code, the driver specific error code and driver specific error string.

Example #1 Create a PDO instance and set the error mode

<?php
$dsn = 'mysql:dbname=testdb;host=127.0.0.1';
$user = 'dbuser';
$password = 'dbpass';

$dbh = new PDO($dsn, $user, $password);
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

// This will cause PDO to throw a PDOException (when the table doesn't exist)
$dbh->query("SELECT wrongcolumn FROM wrongtable");

The above example will output:

Fatal error: Uncaught PDOException: SQLSTATE[42S02]: Base table or view not found: 1146 Table 'testdb.wrongtable' doesn't exist in /tmp/pdo_test.php:10
Stack trace:
#0 /tmp/pdo_test.php(10): PDO->query('SELECT wrongcol...')
#1 {main}
  thrown in /tmp/pdo_test.php on line 10

Note:

PDO::__construct() will always throw a PDOException if the connection fails regardless of which PDO::ATTR_ERRMODE is currently set.

Example #2 Create a PDO instance and set the error mode from the constructor

<?php
$dsn = 'mysql:dbname=test;host=127.0.0.1';
$user = 'googleguy';
$password = 'googleguy';

$dbh = new PDO($dsn, $user, $password, array(PDO::ATTR_ERRMODE => PDO::ERRMODE_WARNING));

// This will cause PDO to throw an error of level E_WARNING instead of an exception (when the table doesn't exist)
$dbh->query("SELECT wrongcolumn FROM wrongtable");

The above example will output:

Warning: PDO::query(): SQLSTATE[42S02]: Base table or view not found: 1146 Table 'test.wrongtable' doesn't exist in
/tmp/pdo_test.php on line 9