PHP Class Prado\Data\ActiveRecord\Relations\TActiveRecordHasOne

The difference of HAS_ONE from HAS_MANY is that the foreign object is singular. That is, HAS_MANY will return a collection of records while HAS_ONE returns the corresponding record. Consider the entity relationship between a Car and a Engine.


+-----+            +--------+
| Car | 1 <----- 1 | Engine |
+-----+            +--------+

Where each engine belongs to only one car, that is, the Engine entity has a foreign key to the Car's primary key. We may model Engine-Car object relationship as active record as follows.


class CarRecord extends TActiveRecord
{
    const TABLE='car';
    public $car_id; //primary key
    public $colour;

    public $engine; //engine foreign object

    public static $RELATIONS=array
    (
        'engine' => array(self::HAS_ONE, 'EngineRecord')
    );

   public static function finder($className=__CLASS__)
   {
	   return parent::finder($className);
   }
}
class EngineRecord extends TActiveRecord
{
    const TABLE='engine';
    public $engine_id;
    public $capacity;
    public $car_id; //foreign key to cars

   public static function finder($className=__CLASS__)
   {
	   return parent::finder($className);
   }
}

The static $RELATIONS property of CarRecord defines that the property $engine that will reference an EngineRecord instance. The car record with engine property list may be fetched as follows.


$cars = CarRecord::finder()->with_engine()->findAll();

The method with_xxx() (where xxx is the relationship property name, in this case, engine) fetchs the corresponding EngineRecords using a second query (not by using a join). The with_xxx() accepts the same arguments as other finder methods of TActiveRecord, e.g. with_engine('capacity < ?', 3.8).

Since: 3.1

Inheritance: extends TActiveRecordRelation

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Public Methods

Method	Description
getRelationForeignKeys ( ) : array
updateAssociatedRecords ( ) : boolean	Updates the associated foreign objects.

Protected Methods

Method	Description
collectForeignObjects ( &$results )	Get the foreign key index values from the results and make calls to the database to find the corresponding foreign objects.
setObjectProperty ( $source, $properties, &$collections )	Sets the foreign objects to the given property on the source object.

Method Details

collectForeignObjects() protected method

Get the foreign key index values from the results and make calls to the database to find the corresponding foreign objects.

protected collectForeignObjects ( &$results )

getRelationForeignKeys() public method

Since: 3.1.2

public getRelationForeignKeys ( ) : array
return	array	foreign key field names as key and object properties as value.

setObjectProperty() protected method

Sets the foreign objects to the given property on the source object.

protected setObjectProperty ( $source, $properties, &$collections )

updateAssociatedRecords() public method

Updates the associated foreign objects.

public updateAssociatedRecords ( ) : boolean
return	boolean	true if all update are success (including if no update was required), false otherwise .