Fuel Documentation

Orm

Orm is short for Object Relational Mapper which does 2 things: it maps your database table rows to objects and it allows you to esteblish relations between those objects.
It follows closely the Active Record Pattern, but was also influenced by other systems.

Relating Models

Usage

The Orm allows for both eager and lazy-loading of relationships. Eager loading means that some (or all) relations are fetched in the original query. Lazy loading means that the relations aren't fetched until you request them.

// eager loading, using joins:
$post = Model_Post::find('all', array('related' => array('comments')));
// or
$post = Model_Post::find()->related('comments')->get();
// $post->comments is available without any further querying after this

// or use lazy loading, it won't use joins but query a relation once requested
// first get a "post", 1 query without join
$post = Model_Post::find('first');
// now request the comments (not yet loaded), which will do another query without join automaticly
$comments = $post->comments;

Basic config

$_has_many = array('comments');

This example, if specified in Model_Article, enables fetching of an array of Model_Comment objects which have the field article_id matching the primary key of a given Article instance through the property comments.

Fully configured

$_has_many = array('comments' => array(
	'model_to' => 'Model_Fancy_Comment',
	'key_from' => 'article_id',
	'key_to' => 'parent_article_id',
	'cascade_save' => true,
	'cascade_delete' => false,
	// there are some more options for specific relation types
));

In the basic example, Orm automatically assumes the model name and field mapping. This example explicitly specifies the class name of the target model, the fields used to relate them, and whether actions performed on the current object should be cascaded to the target. It will return an array of Model_Fancy_Comment object where the comment's parent_article_id field corresponds to the current object's article_id. When saving an object the operation is also performed on its loaded relations, deleting isn't cascaded by default but can be if you switch this on.

Configuration Options

All of the configurations are optional when using the most common naming conventions.

Option Default Notes
model_to Calculated from alias If specified, must the the full class name of the target model (ex. Model_Comment).
By default, this value is formed by prepending 'Model_' to the singular form of the alias (ex. 'comments' becomes 'Model_Comment'), it is also expected to be in the same namespace as the current model.
key_from The key used for the relation in the current model (Usually id) Allows mapping the target model to an arbitrary field in the current model's table
key_to Calculated from the current model name By default, a relationship from a Model_Article to many Model_Comments would use the field article_id in the comments table
cascade_save bool true You can override these options at runtime by passing true as the first argument when calling save() or delete() on the originating model.
cascade_delete bool false

Relation types

The Orm supports the following relationship types natively:

  • Belongs To
    Has the primary key of the relation keps in its table, belongs to 1 related object.
  • Has One
    Has its primary key saved in one other row of another table (which belongs to this), has 1 related object.
  • Has Many
    Has its primary key saved in many other rows of another table (which belong to this one), has many related objects.
  • Many to Many
    Have their primary keys saved in a table in between which keeps pairs of primary keys from both tables. Have and belong to many objects.
  • Many Through
    Same as "Many to Many" but have a model relating them to each other instead of just a 2-column table.

Belongs To

To be written.

Full config example with defaults as values

// in a Model_Comment which belong to a post
$_belongs_to = array(
	'post' => array(
		'key_from' => 'comment_id',
		'model_to' => 'Model_Post',
		'key_to' => 'id',
		'cascade_save' => true,
		'cascade_delete' => false,
	)
);

Has One

Specifies a one-to-one relationship to another model. The target model must include a "Belongs To" reference to the current model to allow the inverse relationship.

Full config example with defaults as values

// in a Model_User which has one profile
$_has_one = array(
	'profile' => array(
		'key_from' => 'id',
		'model_to' => 'Model_Profile',
		'key_to' => 'user_id',
		'cascade_save' => true,
		'cascade_delete' => false,
	)
);

Has Many

Specifies a one-to-many relationship to another model. The target model must include a "Belongs To" reference to the current model to allow the inverse relationship.

Full config example with defaults as values

// in a Model_Post which has many comments
$_has_many = array(
	'comments' => array(
		'key_from' => 'id',
		'model_to' => 'Model_Comment',
		'key_to' => 'post_id',
		'cascade_save' => true,
		'cascade_delete' => false,
	)
);

Many to Many

To be written.

Full config example with defaults as values

// in a Model_Post which has and belongs to many Users
// = multiple posts per user and multiple users (authors) per post
$_many_many = array(
	'users' => array(
		'key_from' => 'id',
		'key_through_from' => 'post_id', // column 1 from the table in between, should match a posts.id
		'table_through' => 'posts_users', // both models plural without prefix in alphabetical order
		'key_through_to' => 'user_id', // column 2 from the table in between, should match a users.id
		'model_to' => 'Model_User',
		'key_to' => 'id',
		'cascade_save' => true,
		'cascade_delete' => false,
	)
);

Many Through

To be written.

Saving/deleting these are not yet supported directly, need to be done through the model connecting them.

Full config example with defaults as values

// in a Model_Post which has and belongs to many Users with a model in between
// = multiple posts per user and multiple users (authors) per post
$_many_through = array(
	'users' => array(
		'key_from' => 'id',
		'key_through_from' => 'post_id', // column 1 from the table in between, should match a posts.id
		'model_through' => 'Model_Posts_Users', // both models plural without prefix in alphabetical order
		'key_through_to' => 'user_id', // column 2 from the table in between, should match a users.id
		'model_to' => 'Model_User',
		'key_to' => 'id',
		'cascade_save' => true,
		'cascade_delete' => false,
	)
);