flask-sqlalchemy，一對多關係，外鍵更改爲NULL

我有用戶表和專輯表等等。而用戶相冊有一對多的關係。flask-sqlalchemy，一對多關係，外鍵更改爲NULL

但是，當用戶與一個或多個專輯相關聯時，不包括來自專輯表中的最新專輯的外鍵將更改爲空。 This is the case that user_uid=1 have 3 albums and user_uid=2 have 1 album.(BUT foreign key having user_uid=1 is only just one.而且這個問題在任何地方都有一對多的關係。這裏是我的代碼..

class User(Base): 
__tablename__ = 'user' 

uid = Column(Integer, primary_key=True) 
username = Column(String(10), unique=True, nullable=False) 
email = Column(String(35), unique=True, nullable=False) 
salted_password = Column(String(100), unique=True, nullable=False) 
profile_pic = Column(String(100)) 
authorization = Column(Boolean) 
expiry = Column(DATETIME) 
fcm_token = Column(String(45)) 
created_at = Column(DATETIME) 
albums = relationship('Album') 
notifications = relationship('Notification') 
like_photo = relationship('Photo', secondary=like_photo) 
follow_album = relationship('Album', secondary=follow_album) 
followed = relationship('User', 
          secondary=followers, 
          primaryjoin=(followers.c.follower_id == uid), 
          secondaryjoin=(followers.c.followed_id == uid), 
          backref=backref('followers', lazy='dynamic'), 
          lazy='dynamic') 
comment_photo = relationship('Photo', secondary=comment) 




class Album(Base): 
__tablename__ = 'album' 

aid = Column(Integer, primary_key=True) 
title = Column(String(45), nullable=False) 
created_at = Column(DATETIME) 
user_uid = Column(Integer, ForeignKey('user.uid')) 
photos = relationship('Photo') 
album_tags = relationship('Album_tag')

我更新專輯表像下面..

u = User.query.filter(User.uid == session['uid']).first() 
u.albums = [Album(title=request.json['title'], created_at=datetime.utcnow())]    
db_session.add(u) 
db_session.commit()

我不知道爲什麼..

來源

2017-04-04 조민주

你可以張貼代碼與你如何發佈數據到你的表嗎？用戶和專輯表？ –

（首先我找到用戶'你'誰在會話中）u.albums = [專輯（標題= request.json ['標題']，created_at = datetime.utcnow（））]; db_session.add（U）; db_session.commit（）; –

我認爲你這樣做是爲了覆蓋專輯列表，最好是用相反的方式來創建專輯，然後分配它的Album.user_uid = u.uid –

我相信你需要做其他因爲在你的方式，你是壓倒性的用戶的相冊列表：

coffee_album = Album(title=request.json['title'], \ 
        created_at=datetime.utcnow()) 
u = User.query.filter(User.uid == session['uid']).first() 
coffe_album.user_uid = u.uid 
db_session.add(coffee_album) 
db_session.commit()

來源

2017-04-04 16:21:02

偉大的解決方案。謝謝。 – joshlsullivan

flask-sqlalchemy，一對多關係，外鍵更改爲NULL

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