from sqlalchemy.ext.declarative import declarative_base

Base=declarative_base()

from sqlalchemy import Column,String,Integer,ForeignKey

from sqlalchemy.orm import relationship

class Girl(Base):

    __tablename__="girl"

    id = Column(Integer,primary_key=True)

    name=Column(String(32))

#secondary="Hotel" 表示两个表关联Hotel

    girl2boy = relationship("Boy",secondary="hotel",backref="boy2girl" )

class Boy(Base):

    __tablename__ = "boy"

    id = Column(Integer,primary_key=True)

    name = Column(String(32))

class Hotel(Base):

    __tablename__ = "hotel"

    id=Column(Integer,primary_key=True)

    girl_id =Column(Integer,ForeignKey("girl.id"))

    boy_id=Column(Integer,ForeignKey("boy.id"))

from sqlalchemy import create_engine

engine=create_engine("mysql+pymysql://root:@127.0.0.1:3306/day127?charset=utf8")

Base.metadata.create_all(engine)

from sqlalchemy.orm import sessionmaker

from SQL.M_M import engine,Boy

Session=sessionmaker(engine)

db_session=Session()

#反向添加

# boy_obj=Boy(name="kobe")

# boy_obj.boy2girl =[Girl(name="dva"),Girl(name="xiaoemi")]

# db_session.add(boy_obj)

# db_session.commit()

# db_session.close()

#正向添加

# girl_obj=Girl(name="anna",girl2boy=[Boy(name="curry"),Boy(name="green")])

# db_session.add(girl_obj)

# db_session.commit()

# db_session.close()

#正向查询

# g_list=db_session.query(Girl).all()

# for row in g_list:

#     for item in row.girl2boy:

#         print(row.id,row.name,item.name)

#反向查询

b_list=db_session.query(Boy).all()

for row in b_list:

    for item in row.boy2girl:

        print(row.id,row.name,item.name)