Django中的用户表上的多对多关系
问题描述:
我正在写一个应用程序,我需要将数据与用户对关联起来。例如,每个用户对都会有一个与它们相关的兼容性分数,以及多对多的关系,例如他们有共同点的艺术家。我对这样做的最佳方式感到困惑,似乎我会使用1)通过一对一关系扩展User,2)在User表上使用递归关系self,3)耦合与specifying extra fields on M2M relationships,但我不能包裹我的头模型看起来像。Django中的用户表上的多对多关系
这是我当前如何实现这一点,我认为是没有做到这一点的最好办法,因为它需要通过DB对于每个查询两遍:
在models.py(伪代码,假设有一个艺术家类):
class UserProfile(models.Model):
user = models.OneToOneField(User)
zipcode = models.CharField(max_length=16)
def create_user_profile(sender, instance, created, **kwargs):
if created:
profile, created = UserProfile.objects.get_or_create(user=instance)
post_save.connect(create_user_profile, sender=User)
class Score(models.Model):
user = models.ForeignKey(User, related_name='score_first_user')
second_user = models.ForeignKey(User, related_name='score_second_user')
dh_score = models.DecimalField(decimal_places=2, max_digits=5)
cre_date = models.DateTimeField(auto_now_add=True)
upd_date = models.DateTimeField(auto_now=True)
deleted = models.BooleanField()
class Meta:
unique_together = ('user', 'second_user')
class UserArtist(models.Model):
user = models.ForeignKey(User, related_name='userartist_first_user')
second_user = models.ForeignKey(User, related_name='userartist_second_user')
artist = models.ForeignKey(Artist)
cre_date = models.DateTimeField(auto_now_add=True)
upd_date = models.DateTimeField(auto_now=True)
deleted = models.BooleanField()
在views.py
然后我保存使用类似(伪代码)成绩和普通的艺人:
s = Score(user=u, second_user=second_user score=dh_score)
s.save()
和使用的东西他们检索像:
u = User.objects.get(username="%s" % username)
user_scores = Score.objects.filter(Q(user=u.id) | Q(second_user=u.id)).order_by('-dh_score')[:10]
for user_score in user_scores:
# non-relevant logic to determine who is user and who is partner
...
partner_artists = UserArtist.objects.filter((Q(user=u.id) & Q(second_user=partner.id))\
| (Q(user=partner.id) & Q(second_user=u.id))
)
什么是最好的方式来实现这一目标?
答
这里是我所完成的用户到用户数据配对,以及制备向中间表中的M2M关系:
models.py
from django.db import models
from django.contrib.auth.models import User
from django.db.models.signals import post_save
class UserProfile(models.Model):
user = models.OneToOneField(User)
pair = models.ManyToManyField('self', through='PairData', symmetrical=False)
def __unicode__(self):
return "%s's profile" % self.user
def create_user_profile(sender, instance, created, **kwargs):
if created:
profile, created = UserProfile.objects.get_or_create(user=instance)
post_save.connect(create_user_profile, sender=User)
class PairData(models.Model):
first_user = models.ForeignKey(UserProfile, related_name='first_user')
second_user = models.ForeignKey(UserProfile, related_name='second_user')
raw_score = models.DecimalField(decimal_places=4, max_digits=9)
dh_score = models.DecimalField(decimal_places=2, max_digits=5)
distance = models.PositiveIntegerField()
cre_date = models.DateTimeField(auto_now_add=True)
def __unicode__(self):
return u"%s %s %f %d" % (self.first_user, self.second_user, self.dh_score, self.distance)
class Artist(models.Model):
pair = models.ManyToManyField(PairData)
artist_name = models.CharField(max_length=256)
def __unicode__(self):
return u"%s" % self.artist_name
下面是如何的示例我查询的一对数据(views.py):
:与每个相关联的一对def matches(request, username):
user_profile = User.objects.get(username=username).get_profile()
pd = PairData.objects.filter(Q(first_user=user_profile) | Q(second_user=user_profile)).order_by('-dh_score')
和艺术家
def user_profile(request, username):
user_profile = User.objects.get(username=username).get_profile()
viewers_profile = request.user.get_profile()
pair = PairData.objects.filter((Q(first_user=user_profile) & Q(second_user=viewers_profile)) \
| (Q(first_user=viewers_profile) & Q(second_user=user_profile)))
artists = Artist.objects.filter(pair=pair)
如果有更好的方式来查询而不使用Q,请分享!
有人提供了一个我在质疑的答案,这是我最终使用的修改。你可以在实施和测试之前删除它,如果你还在那里,请重新添加,以便我可以接受! – kasceled 2012-04-02 10:09:25