Doctrine\DBAL\Platforms\MySqlPlatform::getListTableForeignKeysSQL PHP Method

    public function getListTableForeignKeysSQL($table, $database = null)
    {
        $table = $this->quoteStringLiteral($table);
        if (null !== $database) {
            $database = $this->quoteStringLiteral($database);
        }
        $sql = "SELECT DISTINCT k.`CONSTRAINT_NAME`, k.`COLUMN_NAME`, k.`REFERENCED_TABLE_NAME`, " . "k.`REFERENCED_COLUMN_NAME` /*!50116 , c.update_rule, c.delete_rule */ " . "FROM information_schema.key_column_usage k /*!50116 " . "INNER JOIN information_schema.referential_constraints c ON " . "  c.constraint_name = k.constraint_name AND " . "  c.table_name = {$table} */ WHERE k.table_name = {$table}";
        $databaseNameSql = null === $database ? 'DATABASE()' : $database;
        $sql .= " AND k.table_schema = {$databaseNameSql} /*!50116 AND c.constraint_schema = {$databaseNameSql} */";
        $sql .= " AND k.`REFERENCED_COLUMN_NAME` is not NULL";
        return $sql;
    }