drf多表断表操作

Posted 2020-12-16 chenwenyin

目录

• settings.py
• models.py
• serialiaers.py
• views.py
• urls.py
• 案例

settings.py

INSTALLED_APPS = [
    # ...
    ‘rest_framework‘,
]

DATABASES = {
    ‘default‘: {
        ‘ENGINE‘: ‘django.db.backends.mysql‘,
        ‘NAME‘: ‘dg_proj‘,
        ‘USER‘: ‘root‘,
        ‘PASSWORD‘: ‘123‘,
    }
}

# 连接mysql数据库

"""
任何__init__文件
import pymysql
pymysql.install_as_MySQLdb()
"""

# 国际化处理

LANGUAGE_CODE = ‘zh-hans‘
TIME_ZONE = ‘Asia/Shanghai‘
USE_I18N = True
USE_L10N = True
USE_TZ = False

# 静态文件的环境配置
MEDIA_URL = ‘/media/‘
MEDIA_ROOT = os.path.join(BASE_DIR, ‘media‘)

models.py

"""
Book表：name、price、img、authors、publish、is_delete、create_time

Pbulish表：name、address、is_delete、create_time

Author表：name、age、is_delete、create_time

AutherDetail表：mobile、author、is_delete、create_time


BaseModel基表
is_delete、create_tiime

上面四个表的创建继承基表。可以继承两个字段

"""


"""
外键处理：
反向查询名字：related_name
表关系：db_constraint + on_delete  
    db_constraint=False => 断开表关系
    on_delete=models.CASCADE  级联
    on_delete=models.SET_NULL, null=True  设置为空
    on_delete=models.SET_DEFAULT, default=0  设置成默认值0
    on_delete=models.DO_NOTHING  不处理
注：多对多关系不需要明确on_delete

"""

"""
1、外键位置：
    一对多 - 外键放多的一方
    一对一 - 从逻辑正反向考虑，如作者表与作者详情表，作者删除级联删除详情，
    详情删除作者依旧存在，所以建议外键在详情表中
    多对多 - 外键在关系表中
    
2、ORM正向方向连表查找：
    正向：通过外键字段 eg: author_detial_obj.author 
    反向：通过related_name的值 eg：author_obj.detail
    注：依赖代码见下方
    
3、连表操作关系：
    1）作者删除，详情级联 - on_delete=models.CASCADE
    2）作者删除，详情置空 - null=True, on_delete=models.SET_NULL
    3）作者删除，详情重置 - default=0, on_delete=models.SET_DEFAULT
    4）作者删除，详情不动 - on_delete=models.DO_NOTHING
    注：拿作者与作者详情表举例
    
4、外键关联字段的参数 - 如何实现 断关联、目前表间操作关系、方向查询字段
    i）作者详情表中的
    author = models.OneToOneField(
        to=‘Author‘,
        related_name=‘detail‘,
        db_constraint=False,
        on_delete=models.CASCADE
    )
    
    ii）图书表中的
    publish = models.ForeignKey(
        to=‘Publish‘,
        related_name=‘books‘,
        db_constraint=False,
        on_delete=models.DO_NOTHING,
    )
    authors = models.ManyToManyField(
        to=‘Author‘
        related_name=‘books‘,
        db_constraint=False,
    )
    注：ManyToManyField不能设置on_delete，OneToOneField、
ForeignKey必须设置on_delete（django1.x系统默认级联，
但是django2.x必须手动明确）
"""

from django.db import models

# 图书管理系统：Book、Author、AuthorDetail、Publish
"""
Book表: name、price、img、authors、publish、is_delete、create_time
Publish表: name、address、is_delete、create_time
Author表: name、age、is_delete、create_time
AuthorDetail表: mobile, author、is_delete、create_time
"""

# 1) 基表(把表相同的字段单独创建出来形成基表,让其他表直接继承即可。)
class BaseModel(models.Model):
    is_delete = models.BooleanField(default=False)
    create_time = models.DateTimeField(auto_now_add=True)

    # 设置 abstract  =True 来声明基表，作为基表的Model不能在数据库中形成对应的表
    class Meta:
        abstract = True

class Book(BaseModel):
    """name、price、img、authors、publish、is_delete、create_time"""
    name = models.CharField(max_length=64)
    price = models.DecimalField(max_digits=5, decimal_places=2)
    img = models.ImageField(upload_to=‘img‘, default=‘img/default.jpg‘)
    publish = models.ForeignKey(
        to=‘Publish‘,
        db_constraint=False,  # 断关联
        related_name=‘books‘,  # 反向查询字段：publish_obj.books 就能访问所有出版的书
        on_delete=models.DO_NOTHING,  # 设置连表操作关系
    )
    authors = models.ManyToManyField(
        to=‘Author‘,
        db_constraint=False,
        related_name=‘books‘
    )

    # 序列化插拔式属性 - 完成自定义字段名完成连表查询
    @property
    def publish_name(self):
        return self.publish.name
　　　# 可插拔设计
    @property
    def author_list(self):
        return self.authors.values(‘name‘, ‘age‘, ‘detail__mobile‘).all()

    class Meta:
        db_table = ‘book‘
        verbose_name = ‘书籍‘
        verbose_name_plural = verbose_name
    def __str__(self):
        return self.name

class Publish(BaseModel):
    """name、address、is_delete、create_time"""
    name = models.CharField(max_length=64)
    address = models.CharField(max_length=64)

    class Meta:
        db_table = ‘publish‘
        verbose_name = ‘出版社‘
        verbose_name_plural = verbose_name
    def __str__(self):
        return self.name

class Author(BaseModel):
    """name、age、is_delete、create_time"""
    name = models.CharField(max_length=64)
    age = models.IntegerField()

    class Meta:
        db_table = ‘author‘
        verbose_name = ‘作者‘
        verbose_name_plural = verbose_name
    def __str__(self):
        return self.name

class AuthorDetail(BaseModel):
    """mobile, author、is_delete、create_time"""
    mobile = models.CharField(max_length=11)
    author = models.OneToOneField(
        to=‘Author‘,
        db_constraint=False,
        related_name=‘detail‘,
        on_delete=models.CASCADE,
    )

    class Meta:
        db_table = ‘author_detail‘
        verbose_name = ‘作者详情‘
        verbose_name_plural = verbose_name
    def __str__(self):
        return ‘%s的详情‘ % self.author.name

serialiaers.py

from rest_framework.serializers import ModelSerializer, SerializerMethodField
from rest_framework.exceptions import ValidationError
from . import models


# 可以单独作为Publish接口的序列化类，也可以作为Book序列化外键publish辅助的序列化组件
class PublishModelSerializer(ModelSerializer):
    class Meta:
        model = models.Publish
        fields = (‘name‘, ‘address‘)
        

class BookModelSerializer1(ModelSerializer):
    # 了解: 该方式设置的序列化字段，必须在fields中声明
    # publish_address = SerializerMethodField()
    # def get_publish_address(self, obj):
    #     return obj.publish.address

    # 自定义连表深度 - 子序列化方式 - 该方式不能参与反序列化，使用在序列化反序列化共存时，不能书写
    publish = PublishModelSerializer() ## 获取关于publish所有属性

    class Meta:
        # 序列化类关联的model类
        model = models.Book
        # 参与序列化的字段
        fields = (‘name‘, ‘price‘, ‘img‘, ‘author_list‘, ‘publish‘)

        # 了解知识点
        # 所有字段
        # fields = ‘__all__‘
        # 与fields不共存，exclude排除哪些字段
        # exclude = (‘id‘, ‘is_delete‘, ‘create_time‘)
        # 自动连表深度
        # depth = 1



## 反序列化
class BookModelDeserializer2(ModelSerializer):
    class Meta:
        model = models.Book
        fields = (‘name‘, ‘price‘, ‘publish‘, ‘authors‘)
        # extra_kwargs 用来完成反序列化字段的 系统校验规则
        extra_kwargs = {
            ‘name‘: {
                ‘required‘: True,
                ‘min_length‘: 1,
                ‘error_messages‘: {
                    ‘required‘: ‘必填项‘,
                    ‘min_length‘: ‘太短‘,
                }
            }
        }
    
    # 局部钩子
    def validate_name(self, value):
        # 书名不能包含 g 字符
        if ‘g‘ in value.lower():
            raise ValidationError(‘该g书不能出版‘)
        return value
    # 全局钩子
    def validate(self, attrs):
        publish = attrs.get(‘publish‘)
        name = attrs.get(‘name‘)
        if models.Book.objects.filter(name=name, publish=publish):
            raise ValidationError({‘book‘: ‘该书已存在‘})
        return attrs
    # ModelSerializer类已经帮我们实现了 create 与 update 方法




"""
(1)、fields中设置所有序列化与反序列化字段

（2）、extra_kwargs划分只序列化字段

　　wirte_only:只反序列化

　　read_only:只序列化

　　自定义字段默认只序列化（read_only）

(3)、设置反序列化所需的系统、局部钩子、全局钩子等校验规则
"""

## 序列化与反序列化合并
class V2BookModelSerializer(ModelSerializer):
    class Meta:
        model = models.Book
        fields = (‘name‘, ‘price‘, ‘img‘, ‘author_list‘, ‘publish_name‘, ‘publish‘, ‘authors‘)
        extra_kwargs = {
            ‘name‘: {
                ‘required‘: True,
                ‘min_length‘: 1,
                ‘error_messages‘: {
                    ‘required‘: ‘必填项‘,
                    ‘min_length‘: ‘太短‘,
                }
            },
            ‘publish‘: {
                ‘write_only‘: True
            },
            ‘authors‘: {
                ‘write_only‘: True
            },
            ‘img‘: {
                ‘read_only‘: True,
            },
            ‘author_list‘: {
                ‘read_only‘: True,
            },
            ‘publish_name‘: {
                ‘read_only‘: True,
            }
        }

    def validate_name(self, value):
        # 书名不能包含 g 字符
        if ‘g‘ in value.lower():
            raise ValidationError(‘该g书不能出版‘)
        return value

    def validate(self, attrs):
        publish = attrs.get(‘publish‘)
        name = attrs.get(‘name‘)
        if models.Book.objects.filter(name=name, publish=publish):
            raise ValidationError({‘book‘: ‘该书已存在‘})
        return attrs

views.py

from rest_framework.response import Response
from rest_framework.views import APIView
from . import models, serializers

class Book(APIView):
    def get(self, request, *args, **kwargs):
        pk = kwargs.get(‘pk‘)
        if pk:
            try:
                book_obj = models.Book.objects.get(pk=pk, is_delete=False)
                book_data = serializers.BookModelSerializer1(book_obj).data
            except:
                return Response({
                    ‘status‘: 1,
                    ‘msg‘: ‘书籍不存在‘
                })
        else:
            book_query = models.Book.objects.filter(is_delete=False).all()
            book_data = serializers.BookModelSerializer1(book_query, many=True).data
        return Response({
            ‘status‘: 0,
            ‘msg‘: ‘ok‘,
            ‘results‘: book_data
        })


    def post(self, request, *args, **kwargs):
        request_data = request.data
        book_ser = serializers.BookModelDeserializer2(data=request_data)
        # raise_exception=True：当校验失败，马上终止当前视图方法，抛异常返回给前台
        book_ser.is_valid(raise_exception=True)
        book_obj = book_ser.save()
        return Response({
            ‘status‘: 0,
            ‘msg‘: ‘ok‘,
            ‘results‘: serializers.BookModelSerializer1(book_obj).data
        })



class V2Book(APIView):
    # 单查：有pk
    # 群查：无pk
    def get(self, request, *args, **kwargs):
        pk = kwargs.get(‘pk‘)
        if pk:
            try:
                book_obj = models.Book.objects.get(pk=pk, is_delete=False)
                book_data = serializers.V2BookModelSerializer(book_obj).data
            except:
                return Response({
                    ‘status‘: 1,
                    ‘msg‘: ‘书籍不存在‘
                })
        else:
            book_query = models.Book.objects.filter(is_delete=False).all()
            book_data = serializers.V2BookModelSerializer(book_query, many=True).data
        return Response({
            ‘status‘: 0,
            ‘msg‘: ‘ok‘,
            ‘results‘: book_data
        })


    # 单增：传的数据是与model对应的字典
    # 群增：传的数据是 装多个 model对应字典 的列表
    def post(self, request, *args, **kwargs):
        request_data = request.data
        if isinstance(request_data, dict):
            many = False
        elif isinstance(request_data, list):
            many = True
        else:
            return Response({
                ‘status‘: 1,
                ‘msg‘: ‘数据有误‘,
            })
        book_ser = serializers.V2BookModelSerializer(data=request_data, many=many)
        # 当校验失败，马上终止当前视图方法，抛异常返回给前台
        book_ser.is_valid(raise_exception=True)
        book_result = book_ser.save()
        return Response({
            ‘status‘: 0,
            ‘msg‘: ‘ok‘,
            ‘results‘: serializers.V2BookModelSerializer(book_result, many=many).data
        })


    # 单删：有pk
    # 群删：有pks   |  {"pks": [1, 2, 3]}
    def delete(self, request, *args, **kwargs):
        pk = kwargs.get(‘pk‘)
        if pk:
            pks = [pk]
        else:
            pks = request.data.get(‘pks‘)
        if models.Book.objects.filter(pk__in=pks, is_delete=False).update(is_delete=True):
            return Response({
                ‘status‘: 0,
                ‘msg‘: ‘删除成功‘,
            })
        return Response({
            ‘status‘: 1,
            ‘msg‘: ‘删除失败‘,
        })

urls.py

urlpatterns = [
    url(r‘^books/$‘, views.Book.as_view()),
    url(r‘^books/(?P<pk>.*)/$‘, views.Book.as_view()),
    
    url(r‘^v2/books/$‘, views.V2Book.as_view()),
    url(r‘^v2/books/(?P<pk>.*)/$‘, views.V2Book.as_view()),
]

案例

"""
models.py
"""
from django.db import models

class BaseModel(models.Model):
    is_delete=models.BooleanField(default=False)
    # auto_now_add=True 只要记录创建，不需要手动插入时间，自动把当前时间插入
    create_time=models.DateTimeField(auto_now_add=True)
    # auto_now=True,只要更新，就会把当前时间插入
    last_update_time=models.DateTimeField(auto_now=True)
    # import datetime
    # create_time=models.DateTimeField(default=datetime.datetime.now)
    class Meta:
        # 单个字段，有索引，有唯一
        # 多个字段，有联合索引，联合唯一
        abstract=True  # 抽象表，不再数据库建立出表

class Book(BaseModel):
    id=models.AutoField(primary_key=True)
    # verbose_name admin中显示中文
    name=models.CharField(max_length=32,verbose_name=‘书名‘,help_text=‘这里填书名‘)
    price=models.DecimalField(max_digits=5,decimal_places=2)
    # 一对多的关系一旦确立，关联字段写在多的一方
    #to_field 默认不写，关联到Publish主键
    #db_constraint=False  逻辑上的关联，实质上没有外键练习，增删不会受外键影响，但是orm查询不影响
    publish=models.ForeignKey(to=‘Publish‘,on_delete=models.DO_NOTHING,db_constraint=False)

    # 多对多，跟作者，关联字段写在 查询次数多的一方

    # 什么时候用自动，什么时候用手动？第三张表只有关联字段，用自动    第三张表有扩展字段，需要手动写
    # 不能写on_delete
    authors=models.ManyToManyField(to=‘Author‘,db_constraint=False)
    class Meta:
        verbose_name_plural=‘图书‘  # admin中表名的显示

    def __str__(self):
        return self.name

    @property
    def publish_name(self):
        return self.publish.name
    # def author_list(self):
    def author_list(self):
        # return self.authors.all().values()

        author_list=self.authors.all()
        # ll=[]
        # for author in author_list:
        #     ll.append({‘name‘:author.name,‘sex‘:author.get_sex_display()})
        # return ll

        return [ {‘name‘:author.name,‘sex‘:author.get_sex_display()} for author in author_list]

class Publish(BaseModel):
    name = models.CharField(max_length=32)
    addr=models.CharField(max_length=32)
    def __str__(self):
        return self.name

    class Meta:
        verbose_name_plural = ‘出版社‘


class Author(BaseModel):
    name=models.CharField(max_length=32)
    sex=models.IntegerField(choices=((1,‘男‘),(2,‘女‘)))
    # 一对一关系，写在查询频率高的一方
    #OneToOneField本质就是ForeignKey+unique，自己手写也可以
    authordetail=models.OneToOneField(to=‘AuthorDetail‘,db_constraint=False,on_delete=models.CASCADE)

    def __str__(self):
        return self.name

    class Meta:
        verbose_name_plural = ‘作者‘

class AuthorDetail(BaseModel):
    mobile=models.CharField(max_length=11)

    class Meta:
        verbose_name_plural = ‘作者详情‘

    def __str__(self):
        return self.mobile

# 二、表断关联
# 1、表之间没有外键关联，但是有外键逻辑关联(有充当外键的字段)
# 2、断关联后不会影响数据库查询效率，但是会极大提高数据库增删改效率（不影响增删改查操作）
# 3、断关联一定要通过逻辑保证表之间数据的安全，不要出现脏数据，代码控制
# 4、断关联
# 5、级联关系
#       作者没了，详情也没：on_delete=models.CASCADE
#       出版社没了，书还是那个出版社出版：on_delete=models.DO_NOTHING
#       部门没了，员工没有部门(空不能)：null=True, on_delete=models.SET_NULL
#       部门没了，员工进入默认部门(默认值)：default=0, on_delete=models.SET_DEFAULT


"""
admin.py
"""
from django.contrib import admin

# Register your models here.
from app02 import models

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



"""
serializers.py
"""
from rest_framework import serializers
from app02 import models

## 重写ListSerializer中的update方法(源码中群更新update方法没写)
class BookListSerializer(serializers.ListSerializer):
    def update(self, instance, validated_data):
        return [
            self.child.update(instance[i], attr) for i,attr in enumerate(validated_data)
        ]

class BookModelSerializer(serializers.ModelSerializer):
    class Meta:
        ## 关联群跟新update方法
        list_serializer_class = BookListSerializer
        model = models.Book
        fields = [‘name‘, ‘price‘, ‘authors‘, ‘publish‘, ‘author_list‘, ‘publish_name‘,]
        extra_kwargs = {
            ‘authors‘: {‘write_only‘:True,},
            ‘publish‘: {‘write_only‘:True,},
            ‘author_list‘: {‘read_only‘:True,},
            ‘publish_name‘: {‘read_only‘:True,},
        }



"""
views.py
"""
from django.shortcuts import render
from rest_framework.generics import GenericAPIView
from app02.serializers import BookModelSerializer
from app02 import models
from utils.response import RespUtil
from rest_framework.pagination import PageNumberPagination
# Create your views here.
from rest_framework.serializers import ListSerializer

## 分页
class SelfPagination(PageNumberPagination):
    page_size = 3
    page_size_query_param = "size"
    max_page_size = 5

class BookGenericAPIView(GenericAPIView):
    book_qs = models.Book.objects.all().filter(is_delete=False)
    queryset = book_qs
    serializer_class = BookModelSerializer

    def get(self, request, *args, **kwargs):
        page_obj = SelfPagination()
        book_list = page_obj.paginate_queryset(self.book_qs, request, self)
        # next_url = page_obj.get_next_link()
        # pr_url = page_obj.get_previous_link()
        pk = kwargs.get(‘pk‘)
        if pk:
            ser = self.serializer_class(self.get_object())
        else:
            ser = self.serializer_class(book_list, many=True)
        return RespUtil(data=ser.data)

    def post(self, request, *args, **kwargs):
        if isinstance(request.data, dict):
            ser = self.serializer_class(data=request.data)
        else:
            ser = self.serializer_class(data=request.data, many=True)
        ser.is_valid(raise_exception=True)
        ser.save()
        return RespUtil(data=ser.data)

    def put(self, request, *args, **kwargs):
        if kwargs.get(‘pk‘):
            book = models.Book.objects.filter(pk=kwargs.get(‘pk‘)).first()
            ser = self.serializer_class(instance=book, data=request.data, partial=True)
        else:
            obj = []
            data = []
            for item in request.data:
                pk = item.pop(‘id‘)
                book = models.Book.objects.filter(pk=pk).first()
                obj.append(book)
                data.append(item)
            ## 不重写update方法循环调用update方法一个个跟新也行
            # for i, v in enumerate(data):
            #     ser = self.serializer_class(instance=obj[i], data=v)
            #     ser.is_valid(raise_exception=True)
            #     ser.save()
            
            ser = self.serializer_class(instance=obj, data=data, many=True)
        ser.is_valid(raise_exception=True)
        ser.save()
        return RespUtil(data=ser.data)

    def delete(self, request, *args, **kwargs):
        pk = kwargs.get(‘pk‘)
        pks = []
        if pk:
            pks.append(pk)
        else:
            pks = request.data.get(‘pks‘)
        res = models.Book.objects.filter(id__in=pks, is_delete=False).update(is_delete=True)
        if res:
            return RespUtil(msg=‘OK‘)
        return RespUtil(msg=‘无要删除的数据‘)


"""
urls.py
"""
from django.conf.urls import url
from app02 import views

urlpatterns = [
    url(r‘^v2/books/$‘, views.BookGenericAPIView.as_view()),
    url(r‘^v2/books/(?P<pk>d+)/‘, views.BookGenericAPIView.as_view()),
]