from sqlalchemy import Column, DateTime, ForeignKey, Integer, String, func from sqlalchemy.orm import backref, relationship from database import Base class Department(Base): __tablename__ = 'department' id = Column(Integer, primary_key=True) name = Column(String) class Employee(Base): __tablename__ = 'employee' id = Column(Integer, primary_key=True) name = Column(String) # Use default=func.now() to set the default hiring time # of an Employee to be the current time when an # Employee record was created hired_on = Column(DateTime, default=func.now()) department_id = Column(Integer, ForeignKey('department.id')) # Use cascade='delete,all' to propagate the deletion of a Department onto its Employees department = relationship( Department, backref=backref('employees', uselist=True, cascade='delete,all'))