这是一个基本示例 - 帖子由用户拥有和喜欢。如何为特定用户选择喜欢的帖子?
import datetime
import peewee
class User(peewee.Model):
name = peewee.CharField(max_length=200)
class Post(peewee.Model):
user = peewee.ForeignKeyField(User)
text = peewee.TextField()
class Like(peewee.Model):
user = peewee.ForeignKeyField(User)
post = peewee.ForeignKeyField(Post)
time = peewee.DateTimeField(default=datetime.datetime.now)
我从Like模型的角度进行查询,使用Like.select()
开始查询并加入Post
模型。好吗?我如何从Post
模型的角度进行查询,即Post.select()...
?
以下是一个充满便利的完整示例:
def check_likes():
user, _ = User.get_or_create(name="John")
post, _ = Post.get_or_create(text="Hello world!", user=user)
like, _ = Like.get_or_create(post=post, user=user)
print("Created: ", user, post, like)
# Get liked posts for user
query_likes = (Like.select()
.where(Like.user == user)
.join(User)
.join(Post))
liked_posts = [like.post for like in query_likes]
print("Liked posts: ", liked_posts)
if __name__ == '__main__':
User.create_table(True)
Post.create_table(True)
Like.create_table(True)
check_likes()
UPD。我现在最终得到了这样的询问:
def liked_by(user_id):
"""Active posts liked by user."""
return (Post.select(Post, User, Like)
.join(User, on=(Post.user == User.id))
.switch(Post)
.join(Like, peewee.JOIN.LEFT_OUTER,
on=(Like.post == Post.id).alias('like'))
.where(Like.user == user_id)
.order_by(Like.time.desc()))
答案 0 :(得分:1)
上面的查询应该有效,但您可以将其修改为:
Like.select(Like, Post)...
您还需要注意如何加入表格。使用'开关'方法:
query_likes = (Like.select(Like, Post) # <<< Add like and post
.where(Like.user == user)
.join(User)
.switch(Like) # <<< You need this.
.join(Post))
liked_posts = [like.post for like in query_likes]
你也可以这样做:
Post.select().join(Like).where(Like.user == some_user)