# Create your models here.
#ORM相关的只能写在这个文件里

from django.db import models
class Userinfo(models.Model):
    id = models.AutoField(primary_key=True) #创建一个自增的主键
    name = models.CharField(null=False,max_length=20,unique=True)    #创建一个varchar(可以保存可变长度的字符串)类型不能为空
    def __str__(self):
        return "<{} {}>".format(self.id,self.name)
    '''
    定义如下：代表自定义表名字不加前缀：库中表名就为 userinfo
    class Meta:
        db_table = "userinfo"
    如果不定义 class Meta 库中表名则为 appweb_userinfo
    '''

class Publisher(models.Model):
    id = models.AutoField(primary_key=True) #创建一个自增的主键
    # unique 唯一的不为空的字段
    name = models.CharField(null=False,max_length=64,unique=True)  #创建一个varchar(可以保存可变长度的字符串)类型不能为空
    addr = models.CharField(max_length=128)
    def __str__(self):
        return "<{} {}>".format(self.id,self.name)

class Book(models.Model):
    id = models.AutoField(primary_key=True)#自增的住建
    title = models.CharField(max_length=64,null=False,unique=True)
    #ForeignKey表示外键
    publisher = models.ForeignKey(to="Publisher",on_delete=models.CASCADE,db_column=False)
    # 这里创建的字段为publisher_id (Django会自动加_id)所以不用写成publisher_id否者就变成了publisher_id_id

    def __str__(self):
        # 两种写法
        return "Book object :%s" %self.title  # 必须返回str
        # return "<Book Object: {}>".format(self.title)
class Author(models.Model):
    id = models.AutoField(primary_key=True)
    name = models.CharField(null=False,max_length=16,unique=True)
    # 告诉ORM 这张表和book表是多对多的关系，ORM自动生成第三章表
    book = models.ManyToManyField(to="Book")
    def __str__(self):
        return "<Author Object: {}>".format(self.name)

class Person(models.Model):
    name = models.CharField(max_length=32)
    age = models.IntegerField(default=18)
    birthday = models.DateField(auto_now_add=True)

    def __str__(self):
        return "<Person:{}>".format(self.name)
    # class Meta:
    #     ordering =  ("birthday",)