为Django模型创建JSON夹具

Question

I have defined model as below:

model.py

class User(models.Model):
    user_id = models.IntegerField()
    user_name = models.CharField(max_length=40)
    email = models.EmailField()
    city = models.CharField(max_length=40)
    class Meta:
        ordering = ['user_id']
        verbose_name = 'User MetaData'
        verbose_name_plural = 'Users MetaData'
    def __unicode__(self):
        return str(self.user_id)

class VideoData(models.Model):
    video = models.CharField(max_length=40)
    time  = models.IntegerField()
    user = models.ForeignKey(User)
    class Meta:
        verbose_name = 'User_Video MetaData'
        verbose_name_plural = 'Users_Video MetaData'

Now I want to update models with "loaddata" command from JSON file. I have a JSON file in the format below:

{  
  "fields":{  
     "user id":12026,
     "user name":"Paul Graham",
     "email":"pgraham0@sun.com",
     "city":"China",
     "VIdeoData":[  
        {  
           "video":"Livetube",
           "time":0
        },
        {  
           "video":"Leexo",
           "time":22
        }
     ]
  },
  "pk":1,
  "model":"graph.user"
},

when I used "manage.py loaddata" command i got

error : "User has no field named u'VideoData'"

How can I update the fields?

Answer 1

I recommend to update your models so that they become related to each other.

For example,to the User model add a many-to-many relationship, possibly with a through table to hold the attributes of such relationship (eg when it was rented/watched by the user)

class User(models.Model):
    user_id = models.IntegerField()

    videos = models.ManyToManyField(VideoData, through='VideoRenting', through_fields=('user', 'videodata'))

    user_name = models.CharField(max_length=40)
    email = models.EmailField()
    city = models.CharField(max_length=40)
    class Meta:
        ordering = ['user_id']
        verbose_name = 'User MetaData'
        verbose_name_plural = 'Users MetaData'
    def __unicode__(self):
        return str(self.user_id)

class VideoRenting(models.Model):
    user = models.ForeignKey(User)
    videodata = models.ForeignKey(VideoData)
    rented_at = models.DateTimeField()

See here for more details.

Obviously you can insert the many-to-many relationship in the VideoData class instead of inside the User class.

Create your objects in the DB, then dump them into JSON with django-admin-dumpdata