Was stimmt nicht mit meinen Beziehungen in SQL Alchemy?
Ich verwende SQLAlchemy mit Flask, um Beziehungen für meine Anwendung zu erstellen. Ich habe kürzlich die Beziehungen umgeschrieben und unabhängig davon, was ich ändere, erhalte ich immer wieder den Fehler:
sqlalchemy.exc.NoForeignKeysError: Could not determine join condition between
parent/child tables on relationship CurriculumVersion.enrollments - there are
no foreign keys linking these tables. Ensure that referencing columns are
associated with a ForeignKey or ForeignKeyConstraint, or specify
a 'primaryjoin' expression.
Auf meinen Modellen:
class User(db.Model, AuthUser):
id = db.Column(db.Integer, primary_key=True)
tf_login = db.Column(db.String(255), unique=True, nullable=False) # can assume is an email
password = db.Column(db.String(120), nullable=False)
salt = db.Column(db.String(80))
role = db.Column(db.String(80)) # for later when have different permission types
zoho_contactid = db.Column(db.String(20), unique=True, nullable=False)
created_asof = db.Column(db.DateTime, default=datetime.datetime.utcnow)
enrollments = db.relationship('Enrollment', backref='enrollment', lazy='dynamic')
firstname = db.Column(db.String(80))
lastname = db.Column(db.String(80))
def __repr__(self):
return '#%d tf_login: %s, First Name: %s Last Name: %s created_asof %s' % (self.id, self.tf_login, self.firstname, self.lastname, self.created_asof)
def __getstate__(self):
return {
'id': self.id,
'tf_login': self.tf_login,
'firstname': self.firstname,
'lastname': self.lastname,
'role': self.role,
'created_asof': self.created_asof,
}
@classmethod
def load_current_user(cls, apply_timeout=True):
data = get_current_user_data(apply_timeout)
if not data:
return None
return cls.query.filter(cls.email==data['email']).one()
return '#%d Course Name: %s, Course Version: %s, Closing Date: %s' %(self.id, self.course_name, self.course_version, self.closing_date)
class Enrollment(db.Model, AuthUser):
id = db.Column(db.Integer, primary_key=True)
user_id = db.Column(db.Integer, db.ForeignKey('user.id'))
version_id = db.Column(db.Integer, db.ForeignKey('curriculumversion.id'))
cohort_id = db.Column(db.Integer, db.ForeignKey('cohort.id'))
def __repr__(self):
return '#%d User ID: %d Version ID: %d, Cohort ID: %d' %(self.id, self.user_id, self.version_id, self.cohort_id)
class Cohort(db.Model, AuthUser):
id = db.Column(db.Integer, primary_key=True)
days_to_completion = db.Column(db.String(20))
course_id = db.Column(db.Integer, db.ForeignKey('course.id'))
enrollments = db.relationship('Enrollment', backref='enrollment', lazy='dynamic')
def __repr__(self):
return '#%d Days To Completion: %s' %(self.id, self.days_to_completion)
class CurriculumVersion(db.Model, AuthUser):
id = db.Column(db.Integer, primary_key=True)
version_number = db.Column(db.String(6))
date_implemented = db.Column(db.DateTime)
course_id = db.Column(db.Integer, db.ForeignKey('course.id'))
enrollments = db.relationship('Enrollment', backref='enrollment', lazy='dynamic')
def __repr__(self):
return '#%d Version Number: %s, Date Implemented: %s' %(self.id, self.version_number, self.date_implemented)
class Course(db.Model, AuthUser):
id = db.Column(db.Integer, primary_key=True)
course_code = db.Column(db.String(20))
course_name = db.Column(db.String(50))
versions = db.relationship('CurriculumVersion', backref='version', lazy='dynamic')
cohorts = db.relationship('Cohort', backref='cohort', lazy='dynamic')
def __repr__(self):
return '#%d Course Code: %s, Course Name: %s' %(self.id, self.course_code, self.course_name)
Jede Hilfe wäre dankbar!