[英]Generate average for ratings in Django models and return with other model
I'm working on a project using Python(3.7) and Django(2.1) in which I'm trying to implement a rating system. 我正在使用Python(3.7)和Django(2.1)开发一个项目,我正在其中实施评分系统。
Note: I have searched a lot and taken a look at various related questions but couldn't find any solution to my specific problem, so don't mark this as duplicated, please! 注意:我进行了很多搜索,并研究了各种相关问题,但找不到针对我特定问题的任何解决方案,因此请不要将其标记为重复项!
I have two models as: 我有两种模型:
From models.py
: 从models.py
:
class Gig(models.Model):
CATEGORY_CHOICES = (
('GD', 'Graphic & Design'),
('DM', 'Digital Marketing'),
('WT', 'Writing & Translation'),
('VA', 'Video & Animation'),
('MA', 'Music & Audio'),
('PT', 'Programming & Tech'),
('FL', 'Fun & Lifestyle'),
)
title = models.CharField(max_length=500)
category = models.CharField(max_length=255, choices=CATEGORY_CHOICES)
description = models.CharField(max_length=1000)
price = models.IntegerField(blank=False)
photo = models.FileField(upload_to='gigs')
status = models.BooleanField(default=True)
user = models.ForeignKey(User, on_delete=models.CASCADE)
created_at = models.DateTimeField(default=timezone.now)
def __str__(self):
return self.title
class GigReview(models.Model):
RATING_RANGE = (
('1', '1'),
('2', '2'),
('3', '3'),
('4', '4'),
('5', '5')
)
user = models.ForeignKey(User, on_delete=models.CASCADE)
gig = models.ForeignKey(Gig, on_delete=models.CASCADE, related_name='rates')
order = models.ForeignKey(Order, on_delete=models.CASCADE, null=True)
rating = models.IntegerField(choices=RATING_RANGE,)
content = models.CharField(max_length=500)
def __str__(self):
return self.content
From views.py
: 从views.py
:
def home(request):
gigs = Gig.objects.filter(status=True)
return render(request, 'home.html', {'gigs': gigs})
So, every Gig
has many reviews and I want to return the average
rating for each gig to the template, how Can I achieve that? 所以,每Gig
有很多评论,我想返回average
评级为每个演出的模板,我怎么能做到这一点?
A simple annotation should get it done in one query (rather than one per Gig
when using a property): 一个简单的注释应该在一个查询中完成它(而不是在使用属性时每个Gig
一个查询):
from django.db.models import Avg
gigs = (Gig.objects
.filter(status=True)
.annotate(avg_review=Avg('rates__rating'))
)
If you want to be able to access the average review value on model level, you could add a property field that aggregates the average value through related models in the Gig
-model: 如果您希望能够访问模型级别的平均评论值,则可以在Gig
-model中添加一个属性字段,以通过相关模型汇总平均值:
class Gig(models.Model):
...
@property
def average_rating(self):
return self.rates.all().aggregate(Avg('rating')).get('rating__avg', 0.00)
# Change 0.00 to whatever default value you want when there
# are no reviews.
And in the template access the value with average_rating
. 然后在模板中访问带有average_rating
的值。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.