Serializer rewrite: update and create methods

View class ：

# How the view class that updates user information calls the serializer 
    user = models.User.objects.filter(id=2)
    ser = seralizer.User_Serialzer(instance=user,data=request.data)
    #instance  The data object to be operated ,data The data to be modified is passed 

# How the view class of the new data calls the serializer 
    ser = seralizer.User_Serializer(data=request.data)
    if ser.is_valid:
        # Coming here means passing the verification 

Serializer .py

from rest_framework import serializers
from rest_framework.exceptions import ValidationError
from testapp import models
class User_Serialzer(serializers.Serializer):
    name = serializers.CharField()
    password=serializers.CharField()
    age = serializers.CharField()
    def update(self, instance, validated_data):
        #instance Is the object to be modified 
        #validated_data It is the modified data passed from the front end ,
        # Here we need to modify the data one by one 
        instance.name = validated_data.get('name')
        instance.password = validated_data.get('password')
        instance.age = validated_data.get('age')
        instance.save()
        # This modification is a three-step method for modifying data objects ,
        '''
        1  Get the object （ Instantiate objects ）
        2  Modify the value through the attribute method 
        3  You have to use save To preserve 
        '''
        return instance
    # Create data , Need to rewrite create Method 
    def create(self, validated_data):
        #validated_data It is the dictionary passed by the front end 
        obj=models.UserS.objects.create(**validated_data)
        if obj:
           return validated_data
        else:
            raise ValidationError(' Failed to create data ')

When is serialization or deserialization ：
 

1、 Get the data object in the database , Passed to serializer , This process is serialization . Is to read the data of the database .

2、 The data collected by the front end is passed to the back end , First pass the basic verification of serializer 、 Hook function verification , Then write to the database . This is the process of deserialization .