django postgresql join operation query

Question

I have Django models as shown below,i need to make a view in which i have to get post.id,post.title,post.description,owner.name,number of likes for that post id.how to make a single query for getting all these details?.any suggestions?

class Post(models.Model):
    title=models.CharField(max_length=150)
    description=models.TextField()
    owner=models.ForeignKey("User")

class User(models.Model):
    name=models.CharField(max_length=200)
    location=models.CharField(max_length=200)

class comment(models.Model):
    post_id=models.ForeignKey("Post", null=True,blank=True)
    user_id=models.ForeignKey("USER")

// #likes may be for post or for comment
class likes(models.Model):
    post_id=models.ForeignKey("Post", null=True,blank=True)
    comment_id=models.ForeignKey("comment", null=True,blank=True)
    user_id=models.ForeignKey("USER")

Answer 1

You can use select_related to join the User model in a single query, and annotate to count the likes for a given post:

from django.db.models import Count

my_id = 42
post = Post.objects.select_related('owner') \
    .annotate(num_likes=Count('likes')) \
    .get(id=my_id)

You can then access the values:

post.id
post.title
post.description
post.owner__name
post.num_likes

Answer 2

这里的 id 只是一个条目，但是我们有多个条目，例如 20,50 等，例如在我的情况下，条目是 2000，我怎样才能运行此代码 2000 次