References

• Flask-SQLAlchemy – Simple Relationships
• SQLAlchemy Docs: Relationship API
• the SQLAlchemy Docs on Relationship Loading Techniques 
• SQLALchemy ORM Relationship Docs
• SQLAlchemy Docs on Defining Constraints

Define a Parent-Child Relationship

class Driver(db.Model):
  __tablename__ = 'drivers'
  id = db.Column(db.Integer, privary_key=True)
  ...
  vehicles = db.relationship('Vehicle', backref='driver' , lazy=True)

class Vehicle(db.Model):
  __tablename__ = 'vehicles'
  id = db.Column(db.Integer, privary_key=True)
  ...
  driver_id = db.Column(db.Integer, db.ForeignKey('drivers.id'), nullable=False)

Beachte: Die backref heisst driver, das der relevante Foreign Key jedoch driver_id!

Erklärungen