• 单改、整体/局部修改、群改接口


    配置:settings.py
    INSTALLED_APPS = [
        # ...
        'rest_framework',
    ]
    
    DATABASES = {
        'default': {
            'ENGINE': 'django.db.backends.mysql',
            'NAME': 'dg_proj',
            'USER': 'root',
            'PASSWORD': '123',
        }
    }
    """
    任何__init__文件
    import pymysql
    pymysql.install_as_MySQLdb()
    """
    
    LANGUAGE_CODE = 'zh-hans'
    TIME_ZONE = 'Asia/Shanghai'
    USE_I18N = True
    USE_L10N = True
    USE_TZ = False
    
    MEDIA_URL = '/media/'
    MEDIA_ROOT = os.path.join(BASE_DIR, 'media')
    
    路由
    # 主
    from django.conf.urls import url, include
    from django.contrib import admin
    from django.views.static import serve
    from django.conf import settings
    urlpatterns = [
        url(r'^admin/', admin.site.urls),
        url(r'^api/', include('api.urls')),
        url(r'^media/(?P<path>.*)', serve, {'document_root': settings.MEDIA_ROOT}),
    ]
    
    # 子
    from django.conf.urls import url
    from . import views
    urlpatterns = [
        
    ]
    

    多表设计

    """
    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
    	
    BaseModel基表
    	is_delete、create_time
    上面四表继承基表,可以继承两个字段
    """
    

    基表

    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
    

    断关联多表关系

    知识点(重点)
    """
    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)
    """
    
    model类
    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
    class BaseModel(models.Model):
        is_delete = models.BooleanField(default=False)
        create_time = models.DateTimeField(auto_now_add=True)
    
        # 作为基表的Model不能在数据库中形成对应的表,设置 abstract = True
        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
    
        @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
    

    序列化

    序列化层:api/serializers.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 BookModelSerializer(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()
    
        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
    
    视图层:api/views.py
    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.BookModelSerializer(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.BookModelSerializer(book_query, many=True).data
            return Response({
                'status': 0,
                'msg': 'ok',
                'results': book_data
            })
    
    
    路由层:api/urls.py
    urlpatterns = [
        url(r'^books/$', views.Book.as_view()),
        url(r'^books/(?P<pk>.*)/$', views.Book.as_view()),
    ]
    
    

    反序列化

    序列化层:api/serializers.py
    class BookModelDeserializer(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
    
    
    
    视图层:api/views.py
    class Book(APIView):
        def post(self, request, *args, **kwargs):
            request_data = request.data
            book_ser = serializers.BookModelDeserializer(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.BookModelSerializer(book_obj).data
            })
    
    
    路由层:api/urls.py
    urlpatterns = [
        url(r'^books/$', views.Book.as_view()),
        url(r'^books/(?P<pk>.*)/$', views.Book.as_view()),
    ]
    
    

    序列化与反序列化整合(重点)

    序列化层:api/serializers.py
    """
    1) fields中设置所有序列化与反序列化字段
    2) extra_kwargs划分只序列化或只反序列化字段
        write_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
    """
    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
    
    视图层:api/views.py
    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',
            })
    
    路由层:api/urls.py
    urlpatterns = [
        url(r'^v2/books/$', views.V2Book.as_view()),
        url(r'^v2/books/(?P<pk>.*)/$', views.V2Book.as_view()),
    ]
    
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  • 原文地址:https://www.cnblogs.com/wkq0220/p/11715517.html
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