Zend\Db\ResultSet¶
Zend\Db\ResultSet
is a sub-component of Zend\Db for abstracting the iteration of rowset producing queries.
While data sources for this can be anything that is iterable, generally a
Zend\Db\Adapter\Driver\ResultInterface
based object is the primary source for retrieving data.
Zend\Db\ResultSet
‘s must implement the Zend\Db\ResultSet\ResultSetInterface
and all sub-components of
Zend\Db that return a ResultSet as part of their API will assume an instance of a ResultSetInterface
should be
returned. In most casts, the Prototype pattern will be used by consuming object to clone a prototype of a ResultSet
and return a specialized ResultSet with a specific data source injected. The interface of ResultSetInterface looks
like this:
1 2 3 4 5 | interface ResultSetInterface extends \Traversable, \Countable
{
public function initialize($dataSource);
public function getFieldCount();
}
|
Quickstart¶
Zend\Db\ResultSet\ResultSet
is the most basic form of a ResultSet object that will expose each row as either an
ArrayObject-like object or an array of row data. By default, Zend\Db\Adapter\Adapter
will use a prototypical
Zend\Db\ResultSet\ResultSet
object for iterating when using the Zend\Db\Adapter\Adapter::query()
method.
The following is an example workflow similar to what one might find inside
Zend\Db\Adapter\Adapter::query()
:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | use Zend\Db\Adapter\Driver\ResultInterface;
use Zend\Db\ResultSet\ResultSet;
$stmt = $driver->createStatement('SELECT * FROM users');
$stmt->prepare();
$result = $stmt->execute($parameters);
if ($result instanceof ResultInterface && $result->isQueryResult()) {
$resultSet = new ResultSet;
$resultSet->initialize($result);
foreach ($resultSet as $row) {
echo $row->my_column . PHP_EOL;
}
}
|
Zend\Db\ResultSet\ResultSet and Zend\Db\ResultSet\AbstractResultSet¶
For most purposes, either a instance of Zend\Db\ResultSet\ResultSet
or a
derivative of Zend\Db\ResultSet\AbstractResultSet
will be being used. The implementation of
the AbstractResultSet
offers the following core functionality:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 | abstract class AbstractResultSet implements Iterator, ResultSetInterface
{
public function initialize($dataSource)
public function getDataSource()
public function getFieldCount()
/** Iterator */
public function next()
public function key()
public function current()
public function valid()
public function rewind()
/** countable */
public function count()
/** get rows as array */
public function toArray()
}
|
Zend\Db\ResultSet\HydratingResultSet¶
Zend\Db\ResultSet\HydratingResultSet
is a more flexible ResultSet
object that allows the developer to
choose an appropriate “hydration strategy” for getting row data into a target object. While iterating over
results, HydratingResultSet
will take a prototype of a target object and clone it once for each row.
The HydratingResultSet
will then hydrate that clone with the row data.
In the example below, rows from the database will be iterated, and during iteration, HydratingRowSet
will use
the Reflection based hydrator to inject the row data directly into the protected members of the cloned UserEntity
object:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 | use Zend\Db\Adapter\Driver\ResultInterface;
use Zend\Db\ResultSet\HydratingResultSet;
use Zend\Stdlib\Hydrator\Reflection as ReflectionHydrator;
class UserEntity {
protected $first_name;
protected $last_name;
public function getFirstName() { return $this->first_name; }
public function getLastName() { return $this->last_name; }
public function setFirstName($first_name) { $this->first_name = $first_name; }
public function setLastName($last_name) { $this->last_name = $last_name; }
}
$stmt = $driver->createStatement($sql);
$stmt->prepare($parameters);
$result = $stmt->execute();
if ($result instanceof ResultInterface && $result->isQueryResult()) {
$resultSet = new HydratingResultSet(new ReflectionHydrator, new UserEntity);
$resultSet->initialize($result);
foreach ($resultSet as $user) {
echo $user->getFirstName() . ' ' . $user->getLastName() . PHP_EOL;
}
}
|
For more information, see the Zend\Stdlib\Hydrator
documentation to get a better sense of the different
strategies that can be employed in order to populate a target object.