AbstractPlatform.php

<?php
abstract class AbstractPlatform
{
    //...

    /**
     * Throw a more specific exception based on a SQL error code.
     *
     * @param   \PDOException $e
     * @throws  \Doctrine\DBAL\DBALException
     * @return  void
     */
    public function throwException(\PDOException $e)
    {
        $error_class = substr((string)$e->getCode(), 0, 2);

        switch ($error_class) {
            // Connection Exception
            case '08':
                // pass, connection exceptions seem to be handled elsewhere?
                break;
            case '0A':
            case '0a':
                $exception = 'FeatureNotSupportedException';
                break;
            case '21':
                $exception = 'CardinalityViolationException';
                break;
            case '22':
                $exception = 'DataException';
                break;
            case '23':
                $exception = 'IntegrityConstraintException';
                break;
            case '24':
                $exception = 'InvalidCursorStateException';
                break;
            case '25':
                $exception = 'InvalidTransationStateException';
                break;
            // ... how many of these do the drivers actual use?
        }

        if (isset($exception)) {
            $exception = 'Doctrine\\DBAL\\Exception\\' . $exception;

            throw new $exception($e->getMessage(), 0, $e);
        }

        // if all else fails, just throw a DBALException
        throw new DBALException($e->getMessage(), 0, $e);
    }

    // ...
}