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  • SQLAlchemy 多对多

    参考官网: https://www.pythoncentral.io/sqlalchemy-orm-examples/  

    员工部门两个表,中间为多对多关系,这种一般需要创建一个中间表。多对多转换成一对多

    from sqlalchemy import Integer, Column, String, ForeignKey
    from sqlalchemy.orm import declarative_base, relationship, backref, sessionmaker
    from sqlalchemy import create_engine
    
    Base = declarative_base()
    
    
    class Department(Base):
        __tablename__ = 'department'
        id = Column(Integer, primary_key=True)
        name = Column(String)
        employees = relationship('Employee', secondary='department_employee')
    
    
    class Employee(Base):
        __tablename__ = 'employee'
        id = Column(Integer, primary_key=True)
        name = Column(String)
        departments = relationship('Department', secondary='department_employee')
    
    
    class DepartmentEmployee(Base):
        __tablename__ = 'department_employee'
        department_id = Column(Integer, ForeignKey('department.id'), primary_key=True)
        employee_id = Column(Integer, ForeignKey('employee.id'), primary_key=True)
    
    
    engine = create_engine("sqlite:///")
    session = sessionmaker()
    session.configure(bind=engine)
    Base.metadata.create_all(engine)
    
    s = session()
    john = Employee(name='Jhon')
    s.add(john)
    it_department = Department(name='IT')
    it_department.employees.append(john)
    s.add(it_department)
    s.commit()
    johnDB = s.query(Employee).filter(Employee.name == 'Jhon').one()
    print(johnDB.name)
    print(johnDB.departments[0].name)
    Please call me JiangYouDang!
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  • 原文地址:https://www.cnblogs.com/luckygxf/p/15057503.html
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