ExtendedModel offers the ability to assign one field in your schema to store any data you want in a serialized JSON array. This lets you add any number of additional properties to a model without altering its schema. An example of this is the User model defined in the user app (see Custom user properties) or the blogPost model in the blog app.
To create an ""extended model"" simply inherit from ExtendedModel instead of Model and define your JSON field in the $_extended_field property like this:
<?php
class MyModel extends ExtendedModel {
public $_extended_field = 'extra';
}
?>
Here's a sample schema for the above model:
create table mymodel (
id int not null auto_increment primary key,
extra text not null
);
In addition, you can also specify validation rules for pre-defined extended properties, as long as you also mark them as extended. This is done in the $verify array that's used to add input validation to a model:
<?php
class MyModel extends ExtendedModel {
public $_extended_field = 'extra';
public $verify = array (
'favorite_food' => array (
'extended' => 1
),
'favorite_color' => array (
'extended' => 1,
'regex' => '/^(red|green|blue|etc)$/'
)
);
}
?>
There are three ways of accessing the extended properties:
First, you can simply grab a copy of the extended field and add items to it like this:
<?php
// fetch an object
$obj = new MyModel (1);
// get the extra field and add to it
$extra = $obj->extra;
$extra['photo'] = 'example.jpg';
// now update the object and save it
$obj->extra = $extra;
$obj->put ();
?>
The second way is through the ext() method, which eliminates the need to grab a copy of the extended field (which ordinarily is required because accessing individual array elements won't trigger PHP's magic __get/__set methods). This lets us rewrite the above as:
<?php
// fetch an object
$obj = new MyModel (1);
// set an extra field and save it
$obj->ext ('photo', 'example.jpg');
$obj->put ();
?>
You can also get values through the same method:
<?php
// fetch an object
$obj = new MyModel (1);
echo $obj->ext ('photo');
?>
Or you can retrieve the full list of extended properties by calling ext() with no arguments:
<?php
// fetch an object
$obj = new MyModel (1);
// these two lines do the same thing
$extra = $obj->extra;
$extra = $obj->ext ();
?>
The third way requires that you pre-define your extended properties like we did in the $verify array above. This isn't always something you can do, but when you can, the magic __get/__set methods will let you access individual extended properties just like they were normal properties of the object, like this:
<?php
// fetch an object
$obj = new MyModel (1);
// can't do this because it's not in $verify
echo $obj->photo;
// but we can do this because it is
echo $obj->favorite_color;
// and we can also say
$obj->favorite_color = 'foobar';
// but remember the input validation? well, this will
// fail because 'foobar' isn't a real color
$obj->put ();
?>