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How to add and delete data in django, many novices are not very clear about this. In order to help you solve this problem, the following editor will explain it in detail. People with this need can come and learn. I hope you can get something.

In web development, the most important thing is the design of the database, that is, the design of the models model. To put it bluntly, the simple web development is the addition, deletion, modification and query of the database. Today, let's take a look at the addition, modification, and deletion of the database. We can use native sql statements to operate the database, but if the operation statements of sql are not complex, we can use django ORM statements, which are encapsulated by some. According to the syntax of ORM, you can add, delete, modify and query the database. With the same ORM statement, you can support the operations of adding, deleting and modifying databases such as mysql, sqlite, PostgreSQL, Oracle, etc., with strong compatibility.

My current model model has two tables, a student table and a class table. The code is as follows:

Class Student (models.Model): # must inherit # CharField as the string type, and the maximum length must be set by max_length. Verbose_name displays the Chinese meaning of the English field name= models.CharField (max_length=30, verbose_name= "student name") # IntegerField integer age = models.IntegerField (default=16, verbose_name= "student age") # DecimalField floating point type in the background of django. Max_digits=5 indicates that the sum of integer parts and decimal places is less than 5 decimal places represents the maximum number of decimal places, and # null=True indicates that the field can be empty Blank=True indicates that in the admin background, the data column can be empty score = models.DecimalField (verbose_name=' score', max_digits=5, decimal_places=2, null=True, blank=True) # # EmailField. This field must conform to the mailbox format email = models.EmailField (verbose_name=' mailbox', null=True, blank=True) # TextField field text type, and there is no limit on the length introduce = models.TextField (verbose_name= "Student introduction") # DateTimeField is the date type. Auto_now_add=True the creation time of the data, when the data is updated, the time value remains the same # auto_now=True the creation time of the data, and when the data is updated, the time value will also change created_at = models.DateTimeField (auto_now_add=True, verbose_name= "creation time") updated_at = models.DateTimeField (auto_now=True, verbose_name= "update time") # ForeignKey one-to-many foreign keys, for example, there are multiple students in a class. It belongs to the one-to-many table where the foreign key is put into the "many" table. # related_name is a foreign key alias, which is commonly used in django's orm reverse query cls = models.ForeignKey ('Class', related_name= "stu_cls", null=True, on_delete=models.PROTECT).

# the following is the django background field display control class Meta: verbose_name_plural = verbose_name = "student table" def _ _ str__ (self): return self.name

Class Class (models.Model): # Class table name= models.CharField (verbose_name=' class name', max_length=10) created_at = models.DateTimeField (auto_now_add=True, verbose_name= "creation time") updated_at = models.DateTimeField (auto_now=True, verbose_name= "update time")

Def _ _ str__ (self): return self.name

Class Meta: verbose_name = verbose_name_plural = 'class'

Then synchronize the database, open the terminal (Terminal) in pycharm and enter on the command line:

The following is to write a view function in a views.py file and use ORM for basic addition, deletion and modification operations. Remember to configure the corresponding url for the function.

Def orm_test (request): # add a class named 1901. Create is a new method, which can accept multiple field parameters # Class.objects.create (name= "1901") # both a student and a class operation # add a class named 1903 Return a class instance cls_instance = Class.objects.create (name= "1903") # the key on the left of stu_info corresponds to the Student model field, because cls is a foreign key So correspond to a class example stu_info = {"name": "quiet", "age": "18", "score": "67.50", "email": "123@qq.com", "introduce": "I am Jingjing" "cls": cls_instance} Student.objects.create (* * stu_info) # change the name of the class named 1901 to 1901_xiu Filter is filtering and supports multiple parameters. Update is an update method, which supports multiple parameters # Class.objects.filter (name= "1901") .update (name= "1901_xiu") # delete the class named 1901_xiu, and delete is the deletion method # Class.objects.filter (name= "1901_xiu"). Is it helpful for you to read the above content? If you want to know more about the relevant knowledge or read more related articles, please follow the industry information channel, thank you for your support.

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