Django model definition

The time when the INF math data of a decimal student is modified is the time when the boolean type is created.

• Define Model: Inmodels.pyIt is defined in the file. A data table is a model. If the database has three tables: Student, info, and grade, the meaning of the three tables is student table, student information, and class information, the three tables are associated, the students and classes are in one-to-many relationship, and the student-to-student information is in one-to-one relationship. The model is defined as follows.

• Define the Student Model

Class grage (models. model): g_name = models. charfield (max_length = 10, unique = true) # The maximum length is 10, and the class name is unique class meta: db_table = 'grad' # specify the table name as grade. If this parameter is not specified, the default value is application name_grade.

• Define the one-to-many relationship between the student model and the class

Class student (models. model): s_id = models. integerfield (unique = true) # defines the student ID, and the unique s_name = models. charfield (max_length = 20) # define the Student name. The maximum length is 20 s_gender = models. booleanfield (default = 1) # defines the Student gender and boolean type. The default value is 1. True s_age = models. integerfield () # define the student age create_time = models. datetimefield (auto_now_add = true, null = true) # defines the creation time. auto_now_add indicates that it is created at the current time and will not be changed. null = true indicates that it is null by default. If no error is reported, update_time = models. datetimefield (auto_now = true, null = true) # defines the modification time. auto_now indicates each modification. The value in the field is when the modification time is Chinese = models. decimalfield (decimal_places = 1, max_digits = 4, null = true) # define the Chinese score. decimal_places indicates one decimal place, And max_digits = 4 indicates a maximum of four valid places, such as 123.5, allow null math = models. decimalfield (decimal_places = 1, max_digits = 4, null = true) # define the mathematical score grade = models. foreginkey (grade, null = true) # defines foreign key constraints. One Class corresponds to multiple students info = models. onetoonefield (Info, null = true) # defines the 1-to-1 relationship. The student and Student Information Class meta: db_table = 'student '# specifies the table name as student.

• Define the relationship between info model and student 1-to-1

Class Info (models. model): Phone = models. charfield (max_length = 10, null = true) # defines the mobile phone number. The maximum value is 11 characters. Address = models. charfield (max_length = 50, null = true) # defines the address. The maximum value is 50 class meta: db_table = 'info' # specifies the table name.

Django model definition