ORM框架SQLALchem

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint, Index
from sqlalchemy.orm import sessionmaker, relationship
from sqlalchemy import create_engine
engine = create_engine("mysql+pymysql://root:0520@127.0.0.1:3306/db1", max_overflow=5)
Base = declarative_base()
# 创建单表
class UserType(Base):
    __tablename__ = 'usertype'
    nid = Column(Integer, primary_key=True,autoincrement=True)
    caption = Column(String(50),index=True)

class Users(Base):
    __tablename__ = 'users'
    id = Column(Integer, primary_key=True,autoincrement=True)
    name = Column(String(32))
    extra = Column(String(16))
    usertype_id = Column(Integer,ForeignKey("usertype.nid"))

    __table_args__ = (
        UniqueConstraint('id', 'name', name='uix_id_name'),
        Index('ix_name', 'name'),
    )
#创建表格   删除表格
def init_db():
    Base.metadata.create_all(engine)
def drop_db():
    Base.metadata.drop_all(engine)

# init_db()
Session = sessionmaker(bind=engine)
session = Session()
#####################增######################
# obj = UserType(name="alex0")
# # session.add(obj)
# session.add_all([
#     # UserType(caption="黑金"),
#     # UserType(caption="黑钻"),
#     UserType(caption="普通"),
#     UserType(caption="白金"),
# ])
#####################删######################
# session.query(UserType).filter(UserType.nid > 2).delete()
#####################改######################
# session.query(UserType).filter(UserType.nid < 2).update({"caption" : "099"})
# session.query(UserType).filter(UserType.nid == 2).update({UserType.caption: UserType.caption + "099"}, synchronize_session=False)
# session.query(UserType).filter(UserType.nid == 2).update({"num": Users.num + 1}, synchronize_session="evaluate")
#####################改######################
# ret = session.query(UserType).all()
# # for i in ret:
# #     print(i.caption,i.nid)
# # ret = session.query(Users.name, Users.extra).all()
# # ret = session.query(Users).filter_by(name='11').all()
# # ret = session.query(Users).filter_by(name='11').first()
# session.commit()
# session.close()
#　条件
# ret = session.query(Users).filter_by(name='alex').all()
# ret = session.query(Users).filter(Users.id > 1, Users.name == 'eric').all()
# ret = session.query(Users).filter(Users.id.between(1, 3), Users.name == 'eric').all()
# ret = session.query(Users).filter(Users.id.in_([1,3,4])).all()
# ret = session.query(Users).filter(~Users.id.in_([1,3,4])).all()
# ret = session.query(Users).filter(Users.id.in_(session.query(Users.id).filter_by(name='eric'))).all()
# from sqlalchemy import and_, or_
# ret = session.query(Users).filter(and_(Users.id > 3, Users.name == 'eric')).all()
# ret = session.query(Users).filter(or_(Users.id < 2, Users.name == 'eric')).all()
# ret = session.query(Users).filter(
#     or_(
#         Users.id < 2,
#         and_(Users.name == 'eric', Users.id > 3),
#         Users.extra != ""
#     )).all()
#
#
# # 通配符
# ret = session.query(Users).filter(Users.name.like('e%')).all()
# ret = session.query(Users).filter(~Users.name.like('e%')).all()
#
# # 限制
# ret = session.query(Users)[1:2]
#
# # 排序
# ret = session.query(Users).order_by(Users.name.desc()).all()
# ret = session.query(Users).order_by(Users.name.desc(), Users.id.asc()).all()
#
# # 分组
# from sqlalchemy.sql import func
#
# ret = session.query(Users).group_by(Users.extra).all()
# ret = session.query(
#     func.max(Users.id),
#     func.sum(Users.id),
#     func.min(Users.id)).group_by(Users.name).all()
#
# ret = session.query(
#     func.max(Users.id),
#     func.sum(Users.id),
#     func.min(Users.id)).group_by(Users.name).having(func.min(Users.id) >2).all()
#
# # 连表
#
# ret = session.query(Users, Favor).filter(Users.id == Favor.nid).all()
#
# ret = session.query(Person).join(Favor).all()
#连表 join on
# ret = session.query(Person).join(Favor, isouter=True).all()
#
#
# # 组合
# q1 = session.query(Users.name).filter(Users.id > 2)
# q2 = session.query(Favor.caption).filter(Favor.nid < 2)
# ret = q1.union(q2).all()
#
# q1 = session.query(UserType).filter(Users.id > 2).subquery()#查询作为临时表
# q2 = session.query(Favor.caption).filter(Favor.nid < 2)
# ret = q1.union_all(q2).all()

# 问题1. 获取用户信息以及与其关联的用户类型名称(FK,Relationship=>正向操作)
# user_list = session.query(Users,UserType).join(UserType,isouter=True)
# print(user_list)
# for row in user_list:
#     print(row[0].id,row[0].name,row[0].email,row[0].user_type_id,row[1].title)

# user_list = session.query(Users.name,UserType.title).join(UserType,isouter=True).all()
# for row in user_list:
#     print(row[0],row[1],row.name,row.title)


# user_list = session.query(Users)
# for row in user_list:
#     print(row.name,row.id,row.user_type.title)


# 问题2. 获取用户类型
# type_list = session.query(UserType)
# for row in type_list:
#     print(row.id,row.title,session.query(Users).filter(Users.user_type_id == row.id).all())

# type_list = session.query(UserType)
# for row in type_list:
#     print(row.id,row.title,row.xxoo)
#ut = relationship（backref='xx'）反向是个列表[] 卸载外键的table内