django图书管理系统-外键字段的增删改查

from django.db import models

# Create your models here.

class Book(models.Model):
    name = models.CharField(max_length=32)
    price = models.DecimalField(max_digits=8, decimal_places=2)
    publish_date = models.DateTimeField( auto_now_add= True)
    #添加表关联关系
    publish = models.ForeignKey( to=‘Publish‘, on_delete=models.CASCADE )
    authors = models.ManyToManyField( to=‘Author‘)


class Publish( models.Model):
    name = models.CharField(max_length=32)
    addr = models.CharField(max_length=64)
    email = models.EmailField()  #内部实现也是charField，定义为EmailField是为了表单校验

class Author(models.Model):
    name = models.CharField(max_length=32)
    age = models.IntegerField()
    #添加表关联关系
    authordetail = models.OneToOneField( to=‘AuthorDetail‘, on_delete= models.CASCADE)


#切表，是因为不常用的数据单独放一张表， 对经常用的数据也单独放一张表，提高查询的效率
class AuthorDetail(models.Model):
    addr = models.CharField(max_length=32)
    phone = models.IntegerField()

import  os
import  sys

if __name__ == "__main__":
    os.environ.setdefault(‘DJANGO_SETTINGS_MODULE‘, ‘untitled1.settings‘)
    import  django
    django.setup()
    from app02 import  models
    
    #书籍表的增删改查
    #添加数据，方法1
    # models.Book.objects.create( name = "白蛇",price= 66.66,  publish_id = 1 )
    #添加数据，方法2
    publish_obj = models.Publish.objects.filter( pk=3 ).first()
    models.Book.objects.create( name="白蛇", price = 68.89, publish = publish_obj )