What is the difference between m method and d method in thinkphp

The difference between the m method and the d method in thinkphp: 1. The m method does not need to create a model class file, while the d method must create a model class; 2. The d method will instantiate a specific model class, and the m method Instantiation does not require loading a specific model class.

#The operating environment of this article: Windows 10 system, thinkphp v5.1 version, Dell G3 computer.

#What is the difference between the m method and the d method in thinkphp

The D method can automatically detect the model class, if there is a custom model class , the custom model class will be instantiated. If it does not exist, the system's \Think\Model base class will be instantiated. At the same time, the model that has been instantiated will not be instantiated repeatedly.

When the D method instantiates a model class, it usually instantiates a specific model class. If you only perform basic CURD operations on the data table, if you use the M method to instantiate, since there is no need to load Concrete model class, so performance will be higher.

In ThinkPHP, both the M method and the D method are used to instantiate a model class. The M method is used to efficiently instantiate a basic model class, while the D method is used to instantiate a user-defined model class.

Use the m method

If the following situation occurs, please consider using the M method:

Perform simple CURD operations on the data table without complex When only a few tables have more complex business logic, use the M method in combination with the instantiated CommonModel class.

The M method can even simply operate on the data table corresponding to the parameter table name. ：

$User = M('User');

Use D method

If the following situation occurs, please consider using D Method:

You need to use some advanced functions in the ThinkPHP model, such as the automatic verification function (implemented in the create() method), associated models and other business logic that are relatively complex, and involve many tables. The business logic is defined in the custom In the model class (under the Lib/Model directory), if you want to implement these business logic in the operation

In addition, the D method does not support cross-project calls, you need to use:

$User = D( 'User', 'Admin'); // Instantiate the User model under the Admin project $User = D('Admin.User'); // Project grouping is enabled

Tips

After project grouping is enabled, the Model class does not necessarily correspond to the project grouping. Model classes shared among multiple project groups are placed in the Model directory and can be instantiated directly using D('ModelName'). And D('User.UserInfo') does not mean that User must be a project group, or it can just be a classification directory of files under Model. D('User.UserInfo') instantiates the UserInfo model in the User directory. kind.

Summary

Both the M method and the D method can be used directly when the model class file does not exist, but obviously the M method is more efficient; but to use the business logic in the model class, just Method D must be used.

A more vivid metaphor is: Method M is like a computer that has just installed the operating system and can only use some basic functions; while method D is like installing some other functions such as Office on the installed system. , QQ and other application software have more powerful functions, and at the same time, the entire computer runs slower.

The above is a summary of the differences between the M method and the D method. The M method and the D method should be selected based on the actual situation.

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