In thinkphp, the return value of the m method is a Model object; the m method can be understood as the abbreviation of "$m=new Model("user")", and the calling format is "M('[Basic Model Name:]Model name','Data table prefix','Database connection information')", its function is to instantiate a basic model class.
The operating environment of this article: Windows 10 system, ThinkPHP version 5, Dell G3 computer.
The M method can be thought of as the abbreviation of $m=new Model("user"), that is, M() returns a Model object
The M method is used to instantiate a basic model class.
The calling format of the M method:
M('[基础模型名:]模型名','数据表前缀','数据库连接信息')
What are the specific uses of the M method:
1. Instantiate the basic model (Model) class
When no model is defined, we can use the following method to instantiate a model class for operation:
//实例化User模型 $User = M('User'); //执行其他的数据操作 $User->select();
This This method is the simplest and most efficient, because it does not need to define any model classes, so it supports cross-project calls. The disadvantage is also that there is no custom model class, so the relevant business logic cannot be written and only basic CURD operations can be completed.
$User = M('User');
is actually equivalent to:
$User = new Model('User');
means operating the think_user table. The M method also has a singleton function like the D method, and it will not be instantiated repeatedly if called multiple times. The model name parameter of the M method will be automatically converted to lowercase when converted into a data table, which means that ThinkPHP's data table naming specification is in all lowercase format.
2. Instantiate other public model classes
The first way to instantiate is because there is no definition of the model class, so it is difficult to encapsulate some additional logical methods, but In most cases, you may just need to extend some common logic, then you can try the following method.
$User = M('CommonModel:User');
The changed usage is actually equivalent to:
$User = new CommonModel('User');
Because the system's model classes can be automatically loaded, we do not need to manually import the class library before instantiation. The model class CommonModel must inherit Model. We can define some common logical methods in the CommonModel class, which eliminates the need to define specific model classes for each data table. If your project already has more than 100 data tables, most of them are basic For CURD operations, only some models have some complex business logic that needs to be encapsulated, so the combination of the first method and the second method is a good choice.
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