SQLAlchemy ManyToOne關係問題

Question

我想連接兩個模型。

模型＃1被稱爲「組」。它通過starter_id，main_id，dessert_id連接到幾個「團隊」。我想要一個名爲「小組」的字段，其中包含所有連接小組的列表。

class Group(db.Model): 
    __tablename__ = 'groups' 
    id = db.Column(db.Integer, primary_key=True) 
    starter_id = db.Column(db.Integer, db.ForeignKey('teams.id')) 
    main_id = db.Column(db.Integer, db.ForeignKey('teams.id')) 
    dessert_id = db.Column(db.Integer, db.ForeignKey('teams.id')) 

    #Relationships 
    teams = db.relationship('Team', back_populates="group", foreign_keys= \ 
    [starter_1_id, starter_2_id, starter_3_id, main_1_id, main_2_id, main_3_id, \ 
    dessert_1_id, dessert_2_id, dessert_3_id]) 


class Team(db.Model): 
    __tablename__ = 'teams' 
    id = db.Column(db.Integer, primary_key=True) 
    group_id = db.Column(db.Integer, db.ForeignKey('groups.id')) 

    # Relationships 
    group = db.relationship("Group", back_populates="teams", foreign_keys=[group_id]) 

我得到這個錯誤：

sqlalchemy.exc.AmbiguousForeignKeysError: Could not determine join condition 
between parent/child tables on relationship Group.teams - there are multiple 
foreign key paths linking the tables. Specify the 'foreign_keys' argument, 
providing a list of those columns which should be counted as containing a 
foreign key reference to the parent table. 

我顯然不知道如何解決這個錯誤;）

Answer 1

的 「一隊屬於一組」 關係（Team.group）和它的倒數，「一個團隊有很多團隊」（Group.teams），由外鍵Team.group_id給出，所以你需要寫：

teams = db.relationship('Team', back_populates="group", foreign_keys=lambda: Team.group_id)