ThinkPHP study notes four methods of instantiating models_PHP tutorial

Create Action class

[php]

class NewObjectAction extends Action{

public function index(){

//1. Create a basic model

// //1: Instantiate a system database operation class

// //new Model('User') is equivalent to M('User'), placing a table that needs to be operated on in the Model

// //1 Naming:

// // thinkphp has a table name prefix by default, if it is think_user; you can use User or user to obtain it in the Model

// // If it is think_user_message; then use Model('UserMessage'); uppercase means adding a _ in front of the table name

// $User=new Model('User');

// //Call query method

// $list=$User->select();

// dump($list);

// // 2: Cross-model operation; instantiate a table and instantiate a database operation class written by yourself

//Mostly used to extract some public business logic to form a public Model

// //M('user','CommonModel') is equivalent to new CommonModel('user'); model is automatically loaded

//// $user=M('user','CommonModel');

// $user=new CommonModel('user');

// $list=$user->select();

// dump($list);

// $user->modelTest();

//Three: Instantiate a user-defined model

//Mostly used for businesses that do not require more complexity

//1. Manually create a model and create a custom model for the user table, which can encapsulate the functions provided by thinkphp

//$user=new UserModel() is equivalent to D('user');

//D method will throw an exception if the model does not exist, and will only instance one instance. By default, it only supports calling the model under the current application

// $user=new UserModel();

// $list=$user->select();

// dump($list);

// $user->modelTest();

//4. Instantiate an empty model; it is the way of traditional sql statement; table prefix needs to be added

//

$user=new Model();

$list=$user->query('select * from tb_user');

dump($list);

//Group: D('admin.user');

}

}

?>

Two models:

[php]

class CommonModel extends Model{

function modelTest(){

Echo 'test cross -model operation, call the method in the model';

} }

}

?>

[php]

class UserModel extends Model{

function modelTest(){

Echo 'test cross -model operation, call the method in the model';

} }

}

?>

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