示例代码

from sqlalchemy import create_engine

from sqlalchemy.ext.declarative import declarative_base

from sqlalchemy import Integer, Column, String, DATE, Table, BigInteger

#生成引擎

engine = create_engine("mysql+pymysql://root:123456@localhost/mytest?charset=utf8")

#常见ORM基类

Base = declarative_base()

#创建学生表

class Student(Base):

    __tablename__ = 'student'

    id = Column(Integer, primary_key=True)

    name = Column(String(32))

    password = Column(String(64))

    mobile = Column(BigInteger)

    gradesclasses = Column(String(64))

#创建老师表

class Teacher(Base):

    __tablename__ = 'teacher'

    id = Column(Integer, primary_key=True)

    name = Column(String(32))

    password = Column(String(64))

    mobile = Column(BigInteger)

if __name__ == "__main__":

    Base.metadata.create_all(engine)

ORM多外键关联

#ORM多外键关联

from sqlalchemy import create_engine

from sqlalchemy import Integer, ForeignKey, String, Column

from sqlalchemy.ext.declarative import declarative_base

from sqlalchemy.orm import relationship

engine = create_engine("mysql+pymysql://skymyyang:666666@mfgskymyyang.chinacloudapp.cn/myyang",

                       encoding='utf-8')

Base = declarative_base()

class Customer(Base):

    __tablename__ = 'customer'

    id = Column(Integer, primary_key=True)

    name = Column(String(32))

    billing_address_id = Column(Integer, ForeignKey("address.id"))  #账单地址

    shipping_address_id = Column(Integer, ForeignKey("address.id")) #邮寄地址 这两个地址同时关联了 同一个地址表

    billing_address = relationship("Address", foreign_keys = [billing_address_id])

    shipping_address = relationship("Address", foreign_keys = [shipping_address_id])  #通过关联差address表

class Address(Base):

    __tablename__ = 'address'

    id = Column(Integer, primary_key=True)

    street = Column(String(64))

    city = Column(String(64))

    state = Column(String(64))

    def __repr__(self):

        return self.street

Base.metadata.create_all(engine) #创建表结构

然后进行查询以及数据插入

from daynine import orm_mang_fk

from sqlalchemy.orm import session,sessionmaker

Session_class = sessionmaker(bind=orm_mang_fk.engine)

session = Session_class()#生成session实例 相当于cursor

# addr1 = orm_mang_fk.Address(street="Tiantongyuan", city="Changping", state="BJ")

# addr2 = orm_mang_fk.Address(street="Wudaokou", city="Haidian", state="BJ")

# addr3 = orm_mang_fk.Address(street="Yanjiao", city="LangFang", state="HB")

# session.add_all([addr1, addr2, addr3])

# c1 = orm_mang_fk.Customer(name = "skymyyang", billing_address_id = 4, shipping_address_id = 5)

# c2 = orm_mang_fk.Customer(name = "mayun",  billing_address_id = 6, shipping_address_id = 6)

# session.add_all([c1, c2])

# session.commit()

obj = session.query(orm_mang_fk.Customer).filter(orm_mang_fk.Customer.name =="skymyyang").first()

print(obj.name, obj.billing_address, obj.shipping_address)

ORM多对多

#ORM多对多

from sqlalchemy import create_engine

from sqlalchemy import Integer, ForeignKey, String, Column, DATE, Table

from sqlalchemy.ext.declarative import declarative_base

from sqlalchemy.orm import relationship

#创建引擎

engine = create_engine("mysql+pymysql://skymyyang:666666@mfgskymyyang.chinacloudapp.cn/myyang?charset=utf8",encoding='utf-8')

#生成ORM基类

Base = declarative_base()

book_m2m_author = Table('book_m2m_author', Base.metadata,

                        Column('book_id', Integer, ForeignKey('books.id')),

                        Column('author_id', Integer, ForeignKey('authors.id')),

)

class Book(Base):

    __tablename__ = 'books'

    id = Column(Integer, primary_key=True)

    name = Column(String(64))

    pub_date = Column(DATE)

    authors = relationship('Author', secondary=book_m2m_author, backref = 'books')

    def __repr__(self):

        return self.name

class Author(Base):

    __tablename__ = 'authors'

    id = Column(Integer, primary_key=True)

    name = Column(String(32))

    email = Column(String(64))

    def __repr__(self):

        return self.name

if __name__  ==  '__main__':

    Base.metadata.create_all(engine)