Row Gateways

Zend\Db\RowGateway is a sub-component of zend-db that implements the Row Data Gateway pattern described in the book Patterns of Enterprise Application Architecture. Row Data Gateways model individual rows of a database table, and provide methods such as save() and delete() that persist the row to the database. Likewise, after a row from the database is retrieved, it can then be manipulated and save()'d back to the database in the same position (row), or it can be delete()'d from the table.

RowGatewayInterface defines the methods save() and delete():

namespace Zend\Db\RowGateway;

interface RowGatewayInterface
{
    public function save();
    public function delete();
}

Quick start

RowGateway is generally used in conjunction with objects that produce Zend\Db\ResultSets, though it may also be used standalone. To use it standalone, you need an Adapter instance and a set of data to work with.

The following demonstrates a basic use case.

use Zend\Db\RowGateway\RowGateway;

// Query the database:
$resultSet = $adapter->query('SELECT * FROM `user` WHERE `id` = ?', [2]);

// Get array of data:
$rowData = $resultSet->current()->getArrayCopy();

// Create a row gateway:
$rowGateway = new RowGateway('id', 'my_table', $adapter);
$rowGateway->populate($rowData, true);

// Manipulate the row and persist it:
$rowGateway->first_name = 'New Name';
$rowGateway->save();

// Or delete this row:
$rowGateway->delete();

The workflow described above is greatly simplified when RowGateway is used in conjunction with the TableGateway RowGatewayFeature. In that paradigm, select() operations will produce a ResultSet that iterates RowGateway instances.

As an example:

use Zend\Db\TableGateway\Feature\RowGatewayFeature;
use Zend\Db\TableGateway\TableGateway;

$table = new TableGateway('artist', $adapter, new RowGatewayFeature('id'));
$results = $table->select(['id' => 2]);

$artistRow = $results->current();
$artistRow->name = 'New Name';
$artistRow->save();

ActiveRecord Style Objects

If you wish to have custom behaviour in your RowGateway objects — essentially making them behave similarly to the ActiveRecord pattern), pass a prototype object implementing the RowGatewayInterface to the RowGatewayFeature constructor instead of a primary key:

use Zend\Db\TableGateway\Feature\RowGatewayFeature;
use Zend\Db\TableGateway\TableGateway;
use Zend\Db\RowGateway\RowGatewayInterface;

class Artist implements RowGatewayInterface
{
    protected $adapter;

    public function __construct($adapter)
    {
       $this->adapter = $adapter;
    }

    // ... save() and delete() implementations
}

$table = new TableGateway('artist', $adapter, new RowGatewayFeature(new Artist($adapter)));