function Connection::nextId

Overrides Connection::nextId

File

core/lib/Drupal/Core/Database/Driver/sqlite/Connection.php, line 405

Class

Connection

SQLite implementation of \Drupal\Core\Database\Connection.

Namespace

Code

public function nextId($existing_id = 0) {
    $this->startTransaction();
    // We can safely use literal queries here instead of the slower query
    // builder because if a given database breaks here then it can simply
    // override nextId. However, this is unlikely as we deal with short strings
    // and integers and no known databases require special handling for those
    // simple cases. If another transaction wants to write the same row, it will
    // wait until this transaction commits. Also, the return value needs to be
    // set to RETURN_AFFECTED as if it were a real update() query otherwise it
    // is not possible to get the row count properly.
    $affected = $this->query('UPDATE {sequences} SET value = GREATEST(value, :existing_id) + 1', [
        ':existing_id' => $existing_id,
    ], [
        'return' => Database::RETURN_AFFECTED,
    ]);
    if (!$affected) {
        $this->query('INSERT INTO {sequences} (value) VALUES (:existing_id + 1)', [
            ':existing_id' => $existing_id,
        ]);
    }
    // The transaction gets committed when the transaction object gets destroyed
    // because it gets out of scope.
    return $this->query('SELECT value FROM {sequences}')
        ->fetchField();
}