关系数据库模型中的 Django POST 方法

【问题标题】：Django POST method in relational database model关系数据库模型中的 Django POST 方法
【发布时间】：2017-06-10 07:00:49
【问题描述】：

我想为 url 中定义的用户 ID 创建 Object2。下面显示的示例中的 GET 方法工作正常，但我无法创建 POST 方法。我将不胜感激。假设我在数据库中有免费的示例对象：

User:
id

Object1:
id
user_id

Object2:
id
object1_id

在urls.py 中是这样的：

url(r'^users/(?P<user_id>[0-9]+)/object2$', views.UserObject2),

在models.py:

from django.contrib.auth.models import User

class Object1(models.Model):

    user = models.ForeignKey(User)

class Object2(models.Model):

    object1 = models.ForeignKey(Object1)
    object3 = models.ForeignKey(Object3, related_name='object2')

在views.py:

@api_view(['GET', 'POST']) 
def UserObject2(request, user_id): 
    user = User.objects.get(id=user_id)
    if request.method == 'POST':
        serializer = Object2Serializer(data=request.data)
        object1 = Object1.objects.get(user=user)
        if serializer.is_valid():
            serializer.save(object1=object1) 
        else:
            return Response(serializer.errors)
    else:
        object2 = Object2.objects.filter(object1__user=user)
        serializer = Object2Serializer(object2, many=True)
    return Response(serializer.data)

在serializers.py:

from django.contrib.auth.models import User

class Object3Serializer(serializers.ModelSerializer):

    class Meta:
        model = Object3
        depth = 1
        fields = '__all__'

class UserSerializer(serializers.ModelSerializer):

    def create(self, validated_data):
      user = User.objects.create_user(**validated_data)
      return user

    class Meta:
        model = User

        fields = '__all__'

class Object2Serializer(serializers.ModelSerializer):
    object3 = Object3Serializer(read_only=True)
    class Meta:
        model = Object2

        fields = ('object3', 'number', 'date')

class Object1Serializer(serializers.ModelSerializer):

    class Meta:
        model = Object1

        fields = '__all__'

我正在尝试这种方式，但对象class Object2(models.Model): 中的object3 = models.ForeignKey(Object3, related_name='object2') 有问题，也就是说，当我发送 GET 时，我会得到响应：

[
  {
    "id": 14,
    "object3": {
      "sth1": 4,
      "sth2": "response",
      "sth3": "response1",
    },
    "number": 123,
    "date": "2017-06-07",
  }
]

但在 POST 中，我想以这种方式仅发送 object3 的 id：

  {
    "object3": 3,
    "number": 123,
    "date": "2017-06-07"
  }

但是现在我收到奇怪的错误：

(1146, "Table 'name_of_my_table.i' doesn't exist")

但在我看来，要帮助我会很困难。我不知道它为什么要寻找i 表。我没有任何地方定义它。我什至没有名称为 i 的对象。

总而言之，我只想更改 POST。 GET 是正确的。有什么建议吗？

完整的堆栈跟踪：

Internal Server Error: /users/3/object2
Traceback (most recent call last):
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/db/backends/utils.py", line 65, in execute
    return self.cursor.execute(sql, params)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/db/backends/mysql/base.py", line 101, in execute
    return self.cursor.execute(query, args)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/MySQLdb/cursors.py", line 250, in execute
    self.errorhandler(self, exc, value)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/MySQLdb/connections.py", line 50, in defaulterrorhandler
    raise errorvalue
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/MySQLdb/cursors.py", line 247, in execute
    res = self._query(query)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/MySQLdb/cursors.py", line 411, in _query
    rowcount = self._do_query(q)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/MySQLdb/cursors.py", line 374, in _do_query
    db.query(q)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/MySQLdb/connections.py", line 292, in query
    _mysql.connection.query(self, query)
_mysql_exceptions.ProgrammingError: (1146, "Table 'name_of_my_table.i' doesn't exist")

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/core/handlers/exception.py", line 41, in inner
    response = get_response(request)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/core/handlers/base.py", line 187, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/core/handlers/base.py", line 185, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/views/decorators/csrf.py", line 58, in wrapped_view
    return view_func(*args, **kwargs)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/views/generic/base.py", line 68, in view
    return self.dispatch(request, *args, **kwargs)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/rest_framework/views.py", line 489, in dispatch
    response = self.handle_exception(exc)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/rest_framework/views.py", line 449, in handle_exception
    self.raise_uncaught_exception(exc)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/rest_framework/views.py", line 486, in dispatch
    response = handler(request, *args, **kwargs)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/rest_framework/decorators.py", line 52, in handler
    return func(*args, **kwargs)
  File "/Users/myUser/Projects/myProject/Folder/backend/folder/companies/views.py", line 442, in UserObject23
    serializer.save(object1=object1)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/rest_framework/serializers.py", line 215, in save
    self.instance = self.create(validated_data)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/rest_framework/serializers.py", line 916, in create
    instance = ModelClass.objects.create(**validated_data)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/db/models/manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/db/models/query.py", line 393, in create
    obj.save(force_insert=True, using=self.db)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/db/models/base.py", line 806, in save
    force_update=force_update, update_fields=update_fields)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/db/models/base.py", line 836, in save_base
    updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/db/models/base.py", line 922, in _save_table
    result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/db/models/base.py", line 961, in _do_insert
    using=using, raw=raw)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/db/models/manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/db/models/query.py", line 1060, in _insert
    return query.get_compiler(using=using).execute_sql(return_id)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/db/models/sql/compiler.py", line 1099, in execute_sql
    cursor.execute(sql, params)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/db/backends/utils.py", line 80, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/db/backends/utils.py", line 65, in execute
    return self.cursor.execute(sql, params)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/db/utils.py", line 94, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/utils/six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/db/backends/utils.py", line 65, in execute
    return self.cursor.execute(sql, params)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/django/db/backends/mysql/base.py", line 101, in execute
    return self.cursor.execute(query, args)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/MySQLdb/cursors.py", line 250, in execute
    self.errorhandler(self, exc, value)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/MySQLdb/connections.py", line 50, in defaulterrorhandler
    raise errorvalue
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/MySQLdb/cursors.py", line 247, in execute
    res = self._query(query)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/MySQLdb/cursors.py", line 411, in _query
    rowcount = self._do_query(q)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/MySQLdb/cursors.py", line 374, in _do_query
    db.query(q)
  File "/Users/myUser/Projects/myProject/lib/python3.6/site-packages/MySQLdb/connections.py", line 292, in query
    _mysql.connection.query(self, query)
django.db.utils.ProgrammingError: (1146, "Table 'name_of_my_table.i' doesn't exist")
[10/Jun/2017 09:45:32] "POST /users/3/object2 HTTP/1.1" 500 20503

【问题讨论】：

  • 您可以尝试使用 Object2Serializer(data=object2, many=True) 吗？
  • @Rayu 我已经尝试过了，一切似乎都很好，但最终什么都没有添加到数据库中。我已将更改添加到帖子中。

标签： python django python-3.x django-models django-rest-framework


【解决方案1】：

应@OP 的要求重新写下我的答案。

这是一个例子，

@api_view(['GET', 'POST']) 
def UserObject2(request, user_id): 
    user= User.objects.get(id=user_id)
    if request.method == 'POST':
        object1 = Object1.objects.get(user=user)
        serializer = Object2PostSerializer(data=request.data)
        if serializer.is_valid():
            serializer.save(object1=object1) 
        else:
            return Response(serializer.errors)
    else:
        object2 = Object2.objects.filter(object1__user=user)
        serializer = Object2GetSerializer(object2, many=True)
    return Response(serializer.data)

这只是一个例子，我没有尝试或测试过。我写这篇文章只是为了了解你的情况。所以，如有错误请见谅。

编辑

我建议为这两种方法编写单独的序列化程序。

class Object2GetSerializer(serializers.ModelSerializer):
    object3 = Object3Serializer(read_only=True) 
    class Meta: 
        model = Object2 
        fields = ('object3', 'other_fields')

在序列化器中为object3设置字段选项read_only=True，则该字段不会包含在请求的post方法中。

class Object2PostSerializer(serializers.ModelSerializer): 
    class Meta: 
        model = Object2 
        fields = ('object3', 'object1', 'number', 'date')

【讨论】：

  • 这只是一个例子，我有更复杂的对象、模型和数据库，但我想看看例子，然后我会在我的项目中做，所以我会感谢带有 user_id 的版本网址。我只需要使用request.method == 'POST': 发布，因为我有更复杂的GET 和工作葡萄酒。对不起，我应该早点提过。
  • many=True 表示需要传递一个dicts列表，但你只传递了一个对象，这就是引发错误的原因
  • 好吧，它有帮助，但在我看来，我有更复杂的问题，我已经在更新的帖子中描述了。
  • 你能发布完整的堆栈跟踪吗
  • 我看到您没有在 post 方法中从序列化程序中删除many=True
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