By- Sujeet sujeetkv90@gmail.com
CodeIgniter Base Model is an extended CI_Model class to use in your CodeIgniter applications. It provides a bunch of CRUD operation methods to perform database interaction easier in our application, with provision of intelligent table name guessing and assigning primary key of model automatically. It makes database interactions code DRY and also provide inter-model relation feature giving a little bit of ORM flavour.
class Post_model extends MY_Model
{
// model class
}
$this->load->model('post_model', 'post');
$this->post->find(1);
$this->post->findOneById(1);// magic finder
$this->post->findAll();
$this->post->findAll('title, content');
$this->post->findBy(array( 'title' => 'The Demo Post!' ));
$this->post->findByTitle('The Demo Post!');// magic finder
$this->post->findOneBy('status', 1);
$this->post->findOneByStatus(1);// magic finder
$this->post->findValue('title', array( 'id' => 10 ));
$this->post->orderBy('created', 'desc')->limit(20)->findAll();
$this->post->countAll(array( 'status' => 1 ));
$this->post->create(array(
'status' => 1,
'title' => "The Post of Demo!",
'content' => "The demo content."
));
$this->post->updateBy(array( 'id' => 1 ), array( 'status' => 0 ));
$this->post->updateById(1, array( 'status' => 0 ));
$this->post->deleteBy(array( 'id' => 1 ));
$this->post->deleteById(1);Download and put the MY_Model.php file into application/core folder. CodeIgniter will load and initialise this class automatically.
Extend your model classes from MY_Model and all the functionality will be available in your model automatically.
The model will try to guess the name of the table to use, by finding the plural of the model name.
For example:
class Post_model extends MY_Model { }
...will guess a table name as posts. It also works with suffix _m:
class Book_m extends MY_Model { }
...will guess books.
If you need to set table name to something else, you can declare the $table instance variable and set it to the table name:
class Post_model extends MY_Model
{
protected $table = 'blogposts';
}
Some of the CRUD and relation functions use primary key ID column that is assigned automatically by model. You can overwrite this by setting the $primary_key instance variable:
class Post_model extends MY_Model
{
protected $primary_key = 'post_id';
}
MY_Model has support for basic belongs_to and has_many relationships. These relationships are easy to define:
class Post_model extends MY_Model
{
protected $belongs_to = array( 'user' );
protected $has_many = array( 'comments' );
}It will assume that a MY_Model API-compatible model with the singular relationship's name has been defined. By default, this will be <singular of relationship>_model. The above example, for instance, would require two other models:
class User_model extends MY_Model { }
class Comment_model extends MY_Model { }
If you'd like to customise this, you can pass through the model name as a parameter:
class Post_model extends MY_Model
{
protected $belongs_to = array( 'user' => array( 'model' => 'user_m' ) );
protected $has_many = array( 'comments' => array( 'model' => 'model_comments' ) );
}You can then access your related data using the with() method:
$post = $this->post_model->with('user')
->with('comments')
->find(1);The related data will be embedded in the returned value from getById:
echo $post->user->name;
foreach ($post->comments as $comment)
{
echo $comment->content;
}You can access chained related data recursively using the withRecursive() method:
$post = $this->post_model->withRecursive()->find(1);You can pass recursion level to withRecursive() method.
Separate queries will be run to select the data, so where performance is important, a separate JOIN and SELECT call is recommended.
The relation key can also be configured. For belongs_to calls, the related key is on the current object, not the foreign one. Pseudocode:
SELECT * FROM users WHERE id = $post->user_id
...and for a has_many call:
SELECT * FROM comments WHERE post_id = $post->id
To change this, use the foreign_key value when configuring relation:
class Post_model extends MY_Model
{
public $belongs_to = array( 'users' => array( 'foreign_key' => 'post_user_id' ) );
public $has_many = array( 'comments' => array( 'foreign_key' => 'parent_post_id' ) );
}Complete relation format is:
class Post_model extends MY_Model
{
public $has_many = array(
'comments' => array(
'model' => 'model_comments',
'foreign_key' => 'parent_post_id',
'fields' => 'id, content',
'limit' => array(5, 0),
'order' => array('id', 'desc'),
'scope' => array('status' => 1)
)
);
}By default, MY_Model is setup to return objects using CodeIgniter's QueryBuilder's row() and result() methods. If you'd like to use their array counterparts, there are a couple of ways of customising the model.
If you'd like all your calls to use the array methods, you can set the $default_return_type variable to array.
class Book_model extends MY_Model
{
protected $default_return_type = 'array';
}If you'd like just your next call to return a specific type, there are two scoping methods you can use:
$this->book_model->asArray()->find(1);
$this->book_model->asObject()->find(1);You can use magic find methods by calling findBy<PascalCaseFieldName>() or findOneBy<PascalCaseFieldName>() on model's object.
Following both statements are same:
$this->post->findByStatus(1);// magic finder
$this->post->findBy(array( 'status' => 1 ));You can save data to model's table by using save() method. This method will insert or update data based on whether you have passed $primary_key field in data or not.
Following will update the data of record with id = 1:
$this->post->save(array(
'id' => 1,
'title' => "The Post of Demo!",
'content' => "The demo content."
));Following will insert new record with data:
$this->post->save(array(
'title' => "The Post of Demo!",
'content' => "The demo content."
));If table has any of columns named created and modified with type datetime or timestamp, these will automatically be populated with current time value if not provided with data. If you don't want to update modified column's value, just set its value as false in data.
$this->post->save(array(
'id' => 1,
'title' => "The Post of Demo!",
'content' => "The demo content.",
'modified' => false
));We can specify observer/callback method for save() named as brforeSave() in our model. It will be called before any call to save() method. Data to be saved will be passed to beforeSave() and must be return by this method. You can perform any operation (e.g. Validation or Modification) on data in this method. If you don't want to proceed to respective save() method (e.g. in case of invalid data), just retun false from beforeSave() method otherwise return passed data as it is or modified.
public function beforeSave($data, $table){
// do any stuff with $data
return $data;
}Many methods of MY_Model accept parameter named $options. This can be used to call any valid CodeIgniter DB Object's method except get* methods:
$posts = $this->post->findBy(array('status' => 1), "posts.*, authors.name", array(
'join' => array('authors', 'posts.author_id = authors.id', 'left'),
'order_by' => array('posts.id', 'desc')
));
$users = $this->user->findBy(null, "id, first_name, email", array(
'where_in' => array('username', array('Frank', 'Todd', 'James'))
));
$users = $this->user->findBy(null, "id, first_name, email", array(
'like' => array('username', 'James')
));
$users = $this->user->findOneBy(array('status' => 1), null, array(
'select_max' => array('age')
));Many methods of MY_Model accept parameter to pass table name, so that we can use them for any table of database.