我有一个数据库(和模型)情况,如下模式所示:
这是ModelSerialize:
class PostCreateSerializer(serializers.ModelSerializer):
base64image = serializers.CharField(allow_blank=True, required=False)
categories = serializers.ListField(child=serializers.IntegerField(), required=False)
class Meta:
model = Post
fields = ('title', 'text', 'base64image', 'categories')
def create(self, validated_data):
cats = None
if 'categories' in validated_data:
cats = validated_data.pop('categories')
post = Post.objects.create(**validated_data)
if cats is not None:
for cat in cats:
PostCategory.objects.create(postid=post, categoryid=Category.objects.get(id=cat), isprimary=False)
return post
我将这个json发送到api方法
{
"title": "Post Test",
"text": "Body post Test",
"categories": [2,4]
}
ValueError: save() prohibited to prevent data loss due to unsaved related object 'postid'.
Internal Server Error: /api/post/create/
Traceback (most recent call last):
File "/Users/alfdev/Lavori/PushApp/Rumorize/rvenv/lib/python3.4/site-packages/django/core/handlers/base.py", line 149, in get_response
response = self.process_exception_by_middleware(e, request)
File "/Users/alfdev/Lavori/PushApp/Rumorize/rvenv/lib/python3.4/site-packages/django/core/handlers/base.py", line 147, in get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/Users/alfdev/Lavori/PushApp/Rumorize/rvenv/lib/python3.4/site-packages/django/views/decorators/csrf.py", line 58, in wrapped_view
return view_func(*args, **kwargs)
File "/Users/alfdev/Lavori/PushApp/Rumorize/rvenv/lib/python3.4/site-packages/django/views/generic/base.py", line 68, in view
return self.dispatch(request, *args, **kwargs)
File "/Users/alfdev/Lavori/PushApp/Rumorize/rvenv/lib/python3.4/site-packages/rest_framework/views.py", line 466, in dispatch
response = self.handle_exception(exc)
File "/Users/alfdev/Lavori/PushApp/Rumorize/rvenv/lib/python3.4/site-packages/rest_framework/views.py", line 463, in dispatch
response = handler(request, *args, **kwargs)
File "/Users/alfdev/Lavori/PushApp/Rumorize/rvenv/lib/python3.4/site-packages/rest_framework/generics.py", line 192, in post
return self.create(request, *args, **kwargs)
File "/Users/alfdev/Lavori/PushApp/Rumorize/rvenv/lib/python3.4/site-packages/rest_framework/mixins.py", line 21, in create
self.perform_create(serializer)
File "/Users/alfdev/Lavori/PushApp/Rumorize/server/rumorize/contents/views.py", line 117, in perform_create
PostCategory.objects.create(postid=x, categoryid=Category.objects.get(id=cat), isprimary=False)
File "/Users/alfdev/Lavori/PushApp/Rumorize/rvenv/lib/python3.4/site-packages/django/db/models/manager.py", line 122, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/Users/alfdev/Lavori/PushApp/Rumorize/rvenv/lib/python3.4/site-packages/django/db/models/query.py", line 401, in create
obj.save(force_insert=True, using=self.db)
File "/Users/alfdev/Lavori/PushApp/Rumorize/rvenv/lib/python3.4/site-packages/django/db/models/base.py", line 651, in save
"unsaved related object '%s'." % field.name
ValueError: save() prohibited to prevent data loss due to unsaved related object 'postid'.
视图中我的post_create实现:
def perform_create(self, serializer):
# build and save the image
if 'base64image' in serializer.validated_data:
base64_string = serializer.validated_data.pop('base64image')
import base64
import os
import uuid
base64_format, base64_string = base64_string.split(';base64,')
base64_content = base64.b64decode(base64_string)
filename = '{}{}'.format(uuid.uuid4(), utilities.file_extension_from_base64_format(base64_format))
path = os.path.join(MEDIA_ROOT, 'post_photos')
if not os.path.exists(path):
os.makedirs(path)
with open(os.path.join(path, filename), 'wb+') as f:
f.write(base64_content)
serializer.validated_data['image'] = filename
serializer.save(userid=self.request.user, updateuserid=self.request.user, state=1)
更新
现在我得到了这个错误:django.db.models.fields.related_descriptors.relatedObjectDoesNotexist:Post没有ID。
这些是我的模型:
class Post(models.Model):
id = models.BigIntegerField(db_column='ID', primary_key=True, editable=False)
title = models.CharField(db_column='Title', max_length=500)
text = models.TextField(db_column='Text')
createdate = models.DateTimeField(db_column='CreateDate', editable=False, default=datetime.datetime.now)
updatedate = models.DateTimeField(db_column='UpdateDate', blank=True, null=True, editable=False, default=datetime.datetime.now)
updateuserid = models.ForeignKey(User, models.DO_NOTHING, db_column='UpdateUserID', blank=True, null=True, related_name='PostUpdateUser')
userid = models.OneToOneField(User, models.DO_NOTHING, db_column='UserID', related_name='creation_user')
image = models.CharField(db_column='Image', max_length=500, blank=True, null=True)
state = models.SmallIntegerField(db_column='State')
class Meta:
managed = False
db_table = 'post'
verbose_name = 'Post'
verbose_name_plural = 'Posts'
类PostCategory(Models.Model):id=models.bigIntegerField(db_column='id',primary_key=true)#字段名小写。postid=models.foreignkey(Post,models.do_nothing,db_column='postid',related_name='posts_categories')#字段名小写。categoryid=models.foreignkey(Category,models.do_nothing,db_column='categoryid')#字段名小写。isprimary=models.booleanfield(db_column='isprimary')#字段名小写。此字段类型是一种猜测。
class Meta:
managed = False
db_table = 'post_category'
有什么建议吗?谢谢
尝试调用ModelSerializer
的Create
方法,而不是自己创建对象。另外,if语句也不是必需的,对于PostCategory,您可以直接使用ID
字段。
class PostCreateSerializer(serializers.ModelSerializer):
base64image = serializers.CharField(allow_blank=True, required=False)
categories = serializers.ListField(child=serializers.IntegerField(), required=False)
class Meta:
model = Post
fields = ('title', 'text', 'base64image', 'categories')
def create(self, validated_data):
# you don't need the if block
cats = validated_data.pop('categories', None)
# try calling the create method of ModelSerializer
post = super(PostCreateSerializer, self).create(validated_data)
if cats is not None:
for cat in cats:
PostCategory.objects.create(postid_id=post.id, categoryid_id=cat, isprimary=False)
return post
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