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多表表与表关系 增删改查 admin

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今日内容

  1. 多表表与表关系
  2. 增删改查表数据
  3. admin

多表操作

表与表关系

默认指向主键 可能是隐藏主键 djamgo1.1默认级联（models. SET NULL解除级联）

一对一

先建立少的一方

OneToOneField

from django.db import models

# Create your models here.

class Author(models.Model):
    """
    作者表
    一对一
    Author表 au(au_id)关联与AuthorDetail表的nid
    """
    name=models.CharField( max_length=32)
    age=models.IntegerField()
    # authorDetail=models.OneToOneField(to="AuthorDetail",to_field="nid",on_delete=models.CASCADE)
    au=models.OneToOneField("AuthorDetail",on_delete=models.CASCADE)

class AuthorDetail(models.Model):
    """
    作者详细信息表
    """
    birthday=models.DateField()
    telephone=models.CharField(max_length=11)
    addr=models.CharField(max_length=64)
    # class Meta:
        # db_table='authordetail' #指定表名
        # ordering = ['-id',]


class Publish(models.Model):
    """
    出版社表
    """
    name=models.CharField( max_length=32)
    city=models.CharField( max_length=32)

class Book(models.Model):
    """
    书籍表
    """
    title = models.CharField( max_length=32)
    publishDate=models.DateField()
    price=models.DecimalField(max_digits=5,decimal_places=2)
    书籍表的字段publishs关联与Publish表的主键
    publishs=models.ForeignKey(to="Publish",on_delete=models.CASCADE,)
    authors=models.ManyToManyField('Author',)

多对1

1569718263215

ForeignKey
ManyToManyField
from django.db import models

# Create your models here.

class Author(models.Model):
    """
    作者表
    """
    name=models.CharField( max_length=32)
    age=models.IntegerField()
    # authorDetail=models.OneToOneField(to="AuthorDetail",to_field="nid",on_delete=models.CASCADE)
    
    au=models.OneToOneField("AuthorDetail",on_delete=models.CASCADE)

class AuthorDetail(models.Model):
    """
    作者详细信息表
    """
    birthday=models.DateField()
    telephone=models.CharField(max_length=11)
    addr=models.CharField(max_length=64)
    # class Meta:
        # db_table='authordetail' #指定表名
        # ordering = ['-id',]


class Publish(models.Model):
    """
    出版社表
    """
    name=models.CharField( max_length=32)
    city=models.CharField( max_length=32)

class Book(models.Model):
    """
    书籍表
    Book表与Author表通过ManyToManyField实现多对多关系
    会生成第3张表  id会自己生成 字段是 表名_id 
    通过类或实例化对象找到authors找操作第张表
    """
    title = models.CharField( max_length=32)
    publishDate=models.DateField()
    price=models.DecimalField(max_digits=5,decimal_places=2)
    
    publishs=models.ForeignKey(to="Publish",on_delete=models.CASCADE,)
    authors=models.ManyToManyField('Author',)

多对多

ManyToManyField
from django.db import models

# Create your models here.

class Author(models.Model):
    """
    作者表
    """
    name=models.CharField( max_length=32)
    age=models.IntegerField()
    # authorDetail=models.OneToOneField(to="AuthorDetail",to_field="nid",on_delete=models.CASCADE)
    au=models.OneToOneField("AuthorDetail",on_delete=models.CASCADE)

class AuthorDetail(models.Model):
    """
    作者详细信息表
    """
    birthday=models.DateField()
    telephone=models.CharField(max_length=11)
    addr=models.CharField(max_length=64)
    # class Meta:
        # db_table='authordetail' #指定表名
        # ordering = ['-id',]


class Publish(models.Model):
    """
    出版社表
    """
    name=models.CharField( max_length=32)
    city=models.CharField( max_length=32)

class Book(models.Model):
    """
    书籍表
    Book表与Author表通过ManyToManyField实现多对多关系
    会生成第3张表  id会自己生成 字段是 表名_id 
    通过类或实例化对象找到authors找操作第张表
    """
    title = models.CharField( max_length=32)
    publishDate=models.DateField()
    price=models.DecimalField(max_digits=5,decimal_places=2)
    publishs=models.ForeignKey(to="Publish",on_delete=models.CASCADE,)
    authors=models.ManyToManyField('Author',)

增删改查表数据

创建表代码

from django.db import models

# Create your models here.

class Author(models.Model):
    """
    作者表
    """
    name=models.CharField( max_length=32)
    age=models.IntegerField()
    # authorDetail=models.OneToOneField(to="AuthorDetail",to_field="nid",on_delete=models.CASCADE)
    au=models.OneToOneField("AuthorDetail",on_delete=models.CASCADE)

    def __str__(self):
        return self.name

class AuthorDetail(models.Model):
    """
    作者详细信息表
    """
    birthday=models.DateField()
    telephone=models.CharField(max_length=11)
    addr=models.CharField(max_length=64)
    # class Meta:
        # db_table='authordetail' #指定表名
        # ordering = ['-id',]
    def __str__(self):
        return self.telephone + self.addr


class Publish(models.Model):
    """
    出版社表
    """
    name=models.CharField( max_length=32)
    city=models.CharField( max_length=32)
    def __str__(self):
        return self.name

class Book(models.Model):
    """
    书籍表
    """
    title = models.CharField( max_length=32)
    publishDate=models.DateField()
    price=models.DecimalField(max_digits=5,decimal_places=2)
    publishs=models.ForeignKey(to="Publish",on_delete=models.CASCADE,)
    authors=models.ManyToManyField('Author',)

    def __str__(self):
        return self.title

app01 author 作家表

1569755323692

app01 authordetail 作家详细信息

1569755377786

app01 book表

1569755698656

app01 book authors表 第3张表 book作者表

1569755558911

app01 publish表 出版社

1569755860729

增加
一对一
第一种方式
models.Author.objects.create(
    name='海狗',
    age=59,
    au_id=4
)

第2种方式(与id为4的就是一对一关系)ghj
au_obj = models.AuthorDetail.objects.get(id=4)
第一种方式
models.Author.objects.create(
    name='海狗',
    age=59,
    au=au_obj
)

一对多
pub_obj = models.Publish.objects.get(id=3)
models.Book.objects.create(
    title='xx2',
    price=13,
    publishDate='2011-11-12',
    # publishs=pub_obj , #类属性作为关键字时,值为model对象
    publishs_id=3  # 如果关键字为数据库字段名称,那么值为关联数据的值
)

多对多  -- 多对多关系表记录的增加
ziwen = models.Author.objects.get(id=3)
haigou = models.Author.objects.get(id=5)

new_obj = models.Book.objects.create(
    title='海狗产后护理第二部',
    price=0.5,
    publishDate='2019-09-29',
    publishs_id=2,
)

new_obj.authors.add(3, 5)  # #*args  **kwargs
new_obj.authors.add(*[3, 5])  # 用的最多,
new_obj.authors.add(ziwen, haigou)
删除
# 一对一
# models.AuthorDetail.objects.filter(id=3).delete()
# models.Author.objects.filter(id=3).delete()
# 一对多
# models.Publish.objects.filter(id=3).delete()
# models.Book.objects.filter(id=4).delete()

# 多对多
book_obj = models.Book.objects.get(id=2)
# book_obj.authors.add()  # 添加
# book_obj.authors.remove(1)  #删除
# book_obj.authors.clear()  # 清除
# book_obj.authors.set(['1','5'])  # 先清除再添加,相当于修改
改
    # 改
    # ret = models.Publish.objects.get(id=2)
    # models.Book.objects.filter(id=5).update(
    #     # title='华丽丽',
    #     publishs=ret,
    #     # publishs_id=1,
    # )
跨表查询
    # 查询
    # 一对一
    # 关系属性写在表1,关联到表2,那么通过表1的数据去找表2的数据,叫做正向查询,返过来就是反向查询
    # 查询一下王洋的电话号码

    # 正向查询  对象.属性
    # obj = models.Author.objects.filter(name='王洋').first()
    # ph = obj.au.telephone
    # print(ph)

    # 查一下电话号码为120的作者姓名
    # 反向查询  对象.小写的表名
    # obj = models.AuthorDetail.objects.filter(telephone=120).first()
    # ret = obj.author.name  #陈硕
    # print(ret)

    # 一对多
    # 查询一下 海狗的怂逼人生这本书是哪个出版社出版的  正向查询
    # obj = models.Book.objects.filter(title='海狗的怂逼人生').first()
    # ret = obj.publishs.name
    # print(ret)  #24期出版社
    #  查询一下 24期出版社出版过哪些书
    # obj = models.Publish.objects.filter(name='24期出版社').first()
    #
    # ret = obj.book_set.all() #<QuerySet [<Book: 母猪的产后护理>, <Book: 海狗的怂逼人生>]>
    # for i in ret:
    #     print(i.title)

    # 多对多
    # 海狗的怂逼人生 是哪些作者写的 -- 正向查询
    # obj = models.Book.objects.filter(title='海狗的怂逼人生').first()
    # ret = obj.authors.all()
    #
    # print(ret)  #<QuerySet [<Author: 王洋>, <Author: 海狗>]>
    # for i in ret:
    #     print(i.name)

    # 查询一下海狗写了哪些书 -- 反向查询
    # obj = models.Author.objects.filter(name='海狗').first()
    # ret = obj.book_set.all()
    # print(ret)
    # for i in ret:
    #     print(i.publishs.name)
    #     print(i.title)
    # return HttpResponse('ok')

admin添加用户

python manage.py createsuperuser
输入用户名:wuchao
邮箱不用输 直接回车
输入密码:必须超过8位,并且别太简单

admin注册

from django.contrib import admin

# Register your models here.

from app01 import models

admin.site.register(models.Author)
admin.site.register(models.AuthorDetail)
admin.site.register(models.Publish)
admin.site.register(models.Book)

admin添加用户

python manage.py createsuperuser
输入用户名:wuchao
邮箱不用输 直接回车
输入密码:必须超过8位,并且别太简单

admin注册

from django.contrib import admin

# Register your models here.

from app01 import models

admin.site.register(models.Author)
admin.site.register(models.AuthorDetail)
admin.site.register(models.Publish)
admin.site.register(models.Book)

标签：与表,obj,admin,max,length,models,表表,CharField,id
来源： https://www.cnblogs.com/saoqiang/p/11628240.html