python - 外键有问题

Question

所以我的问题出在这段代码的最底部，其中写着“for b in query”。目标是，如果人们评论了另一个人的帖子，则显示主帖子的所有评论的用户名和内容。错误是peewee.OperationalError:没有这样的表:用户。它打印 i.content 很好，但当我尝试打印 b.user.username 时，它​​会抛出错误。

import datetime

from peewee import *


db = SqliteDatabase('practice2.db')


class User(Model):
    """creates the database attributes"""
    username = CharField(unique=True)
    email = CharField(unique=True)
    password = CharField(max_length=100)
    joined_at = DateTimeField(default=datetime.datetime.now)

    class Meta:
        """creates the database"""
        database = db

class Post(Model):
    """creates the database attributes"""
    timestamp = DateField(default=datetime.date.today)
    user = ForeignKeyField(
        rel_model=User,
        related_name='posts'
    )

    title = TextField()

    content = TextField()

    resources_to_remember = TextField()

    time_spent = TextField()

    tags = TextField()

    class Meta:
        """creates the database"""
        database = db

class CommentPost(Model):
    timestamp = DateField(default=datetime.date.today)
    user = ForeignKeyField(
        rel_model=User,
        related_name='user_posts'
    )
    related_post = ForeignKeyField(
        rel_model = Post,
        related_name = 'com_posts')

    content = TextField()


def initialize():
    """connects to the database"""
    db.connect()
    db.create_tables([User, Post, CommentPost], safe=True)

def practice():
    try:
        w = User.create(username="George", email="george@gmail.com", password="KLJSklsjdfkald")
        f_int = User.get(username="George")
        r = Post.create(user= f_int.id, title="My First Post", content="So yeah this is my first post I think it is good.", resources_to_remember="wikipedia", time_spent="23 minutes", tags="hobbies")
        s = Post.create(user= f_int.id, title="My Second Post", content="So yeah this is my second post I think it is good.", resources_to_remember="brittanica", time_spent="24 minutes", tags="hobbies")
        v = CommentPost.create(user=w.id, related_post=r.id, content="Hey, see you tomorrow.")


    except IntegrityError:
        pass
    else:
        print("it worked")
        print("")

    a = Post.get(Post.title=="My First Post")
    for i in a.com_posts:
        print(i.content)
        query = CommentPost.select(CommentPost, User).join(User).where(CommentPost.content == i.content)
        for b in query:
            print(b.user.username)
            print("")

if __name__ == '__main__':
    initialize()
    practice()

Answer 1

您忘记添加:

class Meta:
        """creates the database"""
        database = db

类内部:CommentPost，因此未创建它。