SQLAlchemy 中的多对多递归 table 定义导致 AmbiguousForeignKeysError

Question

我正在尝试创建 table 的 配置文件 ，其中配置文件、测试和文件夹可以是配置文件的子项，但我得到一个 AmbiguousForeignKeysError 当我调用 create_all(db) 时。我对单个 table 的想法，然后通过映射器或关联 table 引用自身似乎应该可行，但我无法让 sqlalchemy 合作。我使用 sqlalchemy 网站上的多对多关系示例来创建我的代码。这是我的片段：

from sqlalchemy import Column, Integer, String, Enum, Table, ForeignKey
from sqlalchemy.orm import relationship,validates
from core.coyote.models import Base #declarative base

association_table = Table('association', Base.metadata,
    Column('left_id', Integer, ForeignKey('profile_member.id')),
    Column('right_id', Integer, ForeignKey('profile_member.id'))
)

class ProfileMember(Base):
    __tablename__ = "profile_member"
    id = Column(Integer, primary_key=True)
    name = Column(String(250),nullable=True)
    type = Column(Enum("Test","Profile","Folder"))
    children = relationship("ProfileMember",secondary=association_table)

我还计划放入一些验证码，以便我可以强制执行一些出身规则。这是我得到的完整错误：

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

任何关于我可以尝试的事情的线索都将不胜感激。

Answer 1

您必须指定如何加入辅助 table:

children = relationship("ProfileMember", secondary=association_table,
                        primaryjoin=id == association_table.c.left_id,
                        secondaryjoin=association_table.c.right_id == id)

SQLAlchemy 中的多对多递归 table 定义导致 AmbiguousForeignKeysError

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