ORM多表查询典型练习

表字段及关系

from django.db import models

class AuthorDetail(models.Model):
    id = models.AutoField(primary_key=True)
    telephone = models.CharField(max_length=11)
    addr = models.CharField(max_length=50)

class Author(models.Model):
    id = models.AutoField(primary_key=True)
    name = models.CharField(max_length=12)
    age = models.IntegerField()
    gender = models.CharField(max_length=5,default='男')
    ad = models.OneToOneField(to='AuthorDetail',to_field='id',on_delete=models.CASCADE)


class Publish(models.Model):
    id = models.AutoField(primary_key=True)
    name = models.CharField(max_length=22)
    city = models.CharField(max_length=20)

class Book(models.Model):
    id = models.AutoField(primary_key=True)
    title = models.CharField(max_length=33)
    price = models.DecimalField(max_digits=8,decimal_places=2)

    ups = models.IntegerField(default=3)
    comments = models.IntegerField(default=1)

    publisher = models.ForeignKey(to='Publish',to_field='id',on_delete=models.CASCADE)
    authors = models.ManyToManyField(to='Author')

表字段及关系