我正在使用Flask-SQLAlchemy和以下内容models.py：
class DomainRoot(db.Model):
# Int/Float fields
id = db.Column(db.Integer, primary_key=True)
# String fields
domain = db.Column(db.String(64), index=True, unique=True)
# DateTime fields
created = db.Column(db.DateTime)
updated = db.Column(db.DateTime)
# ForeignKey relationships
domain_paths = db.relationship('DomainPath', backref='domain_root', lazy='dynamic')
def __repr__(self):
return '<DomainRoot %r>' % (self.domain)
class DomainPath(db.Model):
# Int/Float fields
id = db.Column(db.Integer, primary_key=True)
# String fields
domain_path = db.Column(db.String(256), index=True, unique=True)
# DateTime fields
created = db.Column(db.DateTime)
updated = db.Column(db.DateTime)
# ForeignKey fields
domainroot_id = db.Column(db.Integer, db.ForeignKey('domainroot.id'))
def __repr__(self):
return '<DomainPath %r>' % (self.domain_path)
当我尝试查询DomainRoot对象时，出现错误：
InvalidRequestError: One or more mappers failed to initialize - can't proceed with initialization of other mappers. Original exception was: Could not determine join condition between parent/child tables on relationship DomainRoot.domain_paths - there are no foreign keys linking these tables. Ensure that referencing columns are associated with a ForeignKey or ForeignKeyConstraint, or specify a 'primaryjoin' expression.
据我所知，我已经添加了适当的外键字段。
我在这里做错了什么？
Flask-SQLAlchemydomain_root用下划线自动生成表名。您指的是domainroot没有下划线的。
通常，在同一模型中定义fk和关系会更容易，并且避免使用字符串引用。
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
app = Flask(__name__)
db = SQLAlchemy(app)
class DomainRoot(db.Model):
id = db.Column(db.Integer, primary_key=True)
class DomainPath(db.Model):
id = db.Column(db.Integer, primary_key=True)
root_id = db.Column(db.ForeignKey(DomainRoot.id))
root = db.relationship(DomainRoot, backref='paths')
db.create_all()
db.session.add(DomainRoot(paths=[DomainPath(), DomainPath()]))
db.session.commit()
print(DomainRoot.query.get(1).paths)
[<__main__.DomainPath object at 0x7fc27f443f28>, <__main__.DomainPath object at 0x7fc27f443fd0>]
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