组合模型 - 在控制器中或使用新的PHP MVC层

Question

Having an ActiveRecord style class in php, what is the correct way to pass a model to a view for a model that contains foriegn keys / realtionships to other models? Should my Controller instantiate the related classes (user_id, category_id) and then pass all the information to the view, or should I generate a new layer in between the model and controller that combines the two? In essence I guess I'm asking where the sql "join" queries should go?

In my database I have a table called Article which looks like,

+------------------+------------+------+-----+-------------------+-----------------------------+
| Field            | Type       | Null | Key | Default           | Extra                       |
+------------------+------------+------+-----+-------------------+-----------------------------+
| id               | int(11)    | NO   | PRI | NULL              | auto_increment              |
| user_id          | int(11)    | NO   | MUL | NULL              |                             |
| title            | char(30)   | NO   |     | NULL              |                             |
| subtitle         | char(60)   | YES  |     | NULL              |                             |
| time             | timestamp  | NO   |     | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
| visible          | tinyint(1) | NO   |     | 1                 |                             |
| body             | mediumtext | YES  |     | NULL              |                             |
| category_id      | int(10)    | NO   | MUL | NULL              |                             |
| featured_mediaid | int(10)    | YES  |     | NULL              |                             |
+------------------+------------+------+-----+-------------------+-----------------------------+

I implemented this table in my article class:

Class Article extends DatabaseTable{

    public $id = null;
    public $title = null;
    public $subtitle = null;
    public $body = null;
    public $time = null;
    public $visible = null;
    public $category_id = null;
    public $user_id = null; 
    public $featured_mediaid = null;

/*.....methods for  Article*/

}

and a related table:

+-------------+------------+------+-----+---------+----------------+
| Field       | Type       | Null | Key | Default | Extra          |
+-------------+------------+------+-----+---------+----------------+
| id          | int(11)    | NO   | PRI | NULL    | auto_increment |
| name        | char(50)   | NO   | UNI | NULL    |                |
| description | char(50)   | NO   |     |         |                |
| visible     | tinyint(1) | NO   |     | 1       |                |
+-------------+------------+------+-----+---------+----------------+

and a category class:

Class Category extends DatabaseTable {

    public $id = null;
    public $name = null;
    public $description = null;
    public $visible = null;

    /*... Some methods here */
}

all my classes inherit from DatabaseTable which has the getById method:

Class DatabaseTable {
    // ...
    public static function getById($id){
        try {
            $connection = new PDO(Database::DB_DSN, Database::DB_USERNAME, Database::DB_PASSWORD);
            $sql = "SELECT * FROM " . strtolower(self::get_called()) . " WHERE id = :id";
            $statement = $connection->prepare($sql);
            $statement->bindValue(":id", (int) $id, PDO::PARAM_INT);
            $statement->execute();
            $row = $statement->fetch(PDO::FETCH_ASSOC);
            $connection = null; 
        }
        /*catch(PDOException $exception) {

        }*/
        catch(Exception $exception) {
            echo "An Unknown Exception Occured";
            echo "Calling Class [" . self::get_called() . "] " . "Method [" . __FUNCTION__ . "]" ;
            $connection = null;
            echo $exception->getMessage();
        }
        $class = self::get_called();
        return new $class($row);
    }

    public static function get_called(){
        return get_called_class() ; 
    }
    //...

}

Answer 1

MVC is enough. You don't need to create "new layer" anywhere.

In most cases you only receive(or use a corresponding model method to fetch) and display data in the view side. i.e Controller initiates and pass the models to the view so that view calls the corresponding methods in the model to fetch data.

Having said so, if a table is related to another table, and if you want to get all the data from both tables, you can create method in the "referring" model to do the join and return a combined result. Or if you like, you can do this in the controller side by using the two models and use a key from one table and give it to another model method (as an argument) and finally join/merge the outputs.