1.单表
(1)表结构
(2)orm对应代码
class Publisher(models.Model):
pid = models.AutoField(primary_key=True)
name = models.CharField(max_length=32,unique=True)
2.一对多(ForeignKey)
(1)表结构
(2)orm对应代码
class Book(models.Model):
title = models.CharField(max_length=32)
publisher = models.ForeignKey("Publisher",on_delete=models.CASCADE)
3.多对多(ManytoManyField)
(1)表结构
(2)orm对应代码
django会自动帮我们创建多对多关系表
class Author(models.Model):
name = models.CharField(max_length=32)
books = models.ManyToManyField("Book")
我们可以告诉django我们手动创建
class Author(models.Model):
name = models.CharField(max_length=32)
books = models.ManyToManyField("Book",through="Author_book")
class Author_book(models.Model):
author = models.ForeignKey("Author")
book = models.ForeignKey("Book")