sqlalchemy 多对多关系

# -*- coding: utf-8 -*-

from sqlalchemy import Column, String, create_engine,ForeignKey,Text,Integer,Table
from sqlalchemy.orm import sessionmaker,relationship
from sqlalchemy.ext.declarative import declarative_base

# 创建对象的基类:
Base = declarative_base()
# 初始化数据库连接:
engine = create_engine('mysql+pymysql://root:root@localhost:3306/test')
# # 创建DBSession类型:
# DBSession = sessionmaker(bind=engine)

# Table(
#     'mapping',
#     Base.metadata,
#     Column('id',Integer,autoincrement=True,primary_key=True),
#     Column('recipe_id',Integer,ForeignKey('recipe.id')),
#     Column('ingredient_id',Integer,ForeignKey('ingredient.id'))
# )

arctire_tag = Table(
    "arctire_tag",
    Base.metadata,
    Column('arctire_id',Integer,ForeignKey('arctire.id'),primary_key=True),
    Column("tag_id",Integer , ForeignKey("tag.id"),primary_key=True),
)

class Arctire(Base):
    __tablename__ = "arctire"
    id = Column(Integer , primary_key=True , autoincrement=True)
    name = Column(String(50) , nullable=False)
    tags = relationship("Tag", backref="arctires", secondary='arctire_tag')

    def __repr__(self):
        return "name:%s"%self.name

class Tag(Base):
    __tablename__ = 'tag'
    id = Column(Integer , primary_key=True , autoincrement=True)
    tag = Column(String(50) , nullable=False)

    def __repr__(self):
        return "tag:%s"%self.tag

Base.metadata.create_all(engine)

　　

# -*- coding: utf-8 -*-

from sqlalchemy import Column, String, create_engine,ForeignKey,Text,Integer,Table
from sqlalchemy.orm import sessionmaker,relationship
from sqlalchemy.ext.declarative import declarative_base

# 创建对象的基类:
Base = declarative_base()
# 初始化数据库连接:
engine = create_engine('mysql+pymysql://root:root@localhost:3306/test')
# # 创建DBSession类型:
# DBSession = sessionmaker(bind=engine)

# arctire_tag = Table(
#     "arctire_tag",
#     Base.metadata,
#     Column('arctire_id',Integer,ForeignKey('arctire.id'),primary_key=True),
#     Column("tag_id",Integer , ForeignKey("tag.id"),primary_key=True),
# )

class Arctire_tag(Base):
    __tablename__='arctire_tag'
    arctire_id=Column(Integer,ForeignKey('arctire.id'),primary_key=True)
    tag_id=Column(Integer,ForeignKey('tag.id'),primary_key=True)

class Arctire(Base):
    __tablename__ = "arctire"
    id = Column(Integer , primary_key=True , autoincrement=True)
    name = Column(String(50) , nullable=False)
    tags = relationship("Tag", backref="arctires", secondary='arctire_tag')

    def __repr__(self):
        return "name:%s"%self.name

class Tag(Base):
    __tablename__ = 'tag'
    id = Column(Integer , primary_key=True , autoincrement=True)
    tag = Column(String(50) , nullable=False)

    def __repr__(self):
        return "tag:%s"%self.tag

Base.metadata.create_all(engine)