day13

#!/usr/bin/env python
#-*- coding:utf-8 -*-
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint, Index
from sqlalchemy.orm import sessionmaker, relationship
#创建数据连接引擎
engine = create_engine("mysql+pymysql://root:123.com@192.168.11.233:3306/zeng", max_overflow=5)
Base = declarative_base()
class user(Base):
    __tablename__ = ‘user‘
    nid = Column(Integer,primary_key=True,autoincrement=True)
    username = Column(String(32))
    group_id = Column(Integer,ForeignKey(‘group.nid‘))

class group(Base):
    __tablename__ = ‘group‘
    nid =  Column(Integer,primary_key=True,autoincrement=True)
    name = Column(String(32))
#创建表
# Base.metadata.create_all(engine)
if __name__ == ‘__main__‘:
    Session = sessionmaker(bind=engine)
    session = Session()
    # session.add(group(name=‘DBA‘))
    # session.add(group(name=‘SA‘))
    # session.commit()

    session.add_all([
        user(username=‘alex1‘,group_id=1),
        user(username=‘alex2‘,group_id=2)
    ])
    session.commit()

from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint, Index
from sqlalchemy.orm import sessionmaker, relationship
engine = create_engine("mysql+pymysql://root:123.com@192.168.11.233:3306/zeng", max_overflow=5)

Base = declarative_base()
# 一对多
# class group(Base):
#     __tablename__ = ‘group‘
#     nid = Column(Integer, primary_key=True,autoincrement=True)
#     caption = Column(String(32))
# class user(Base):
#     __tablename__ = ‘user‘
#     nid = Column(Integer, primary_key=True,autoincrement=True)
#     username = Column(String(32))
#     group_id = Column(Integer, ForeignKey(‘group.nid‘))
#     group = relationship("group", backref=‘uuu‘)
#     def __repr__(self):
#         temp = "%s - %s: %s" %(self.nid, self.username, self.group_id)
#         return temp

class user(Base):
    __tablename__ = ‘user‘
    nid = Column(Integer,primary_key=True,autoincrement=True)
    username = Column(String(32))
    group_id = Column(Integer,ForeignKey(‘group.nid‘))


#相当于 把group实例嵌套到user实例中的group字段
    group = relationship("group", backref=‘uuu‘)
    def __repr__(self):
        temp = "%s - %s: %s" %(self.nid, self.username, self.group_id)
        return temp

class group(Base):
    __tablename__ = ‘group‘
    nid =  Column(Integer,primary_key=True,autoincrement=True)
    name = Column(String(32))



#创建表，和删除表
# Base.metadata.create_all(engine)
# Base.metadata.drop_all(engine)

#创建连接
Session = sessionmaker(bind=engine)
session = Session()


#在表中添加信息
# session.add(Group(caption=‘dba‘))
# session.add(Group(caption=‘ddd‘))
#提交
# session.commit()


#在表中添加多条信息
# session.add_all([
#     User(username=‘alex1‘,group_id=1),
#     User(username=‘alex2‘,group_id=2)
# ])
# session.commit()

# 只是获取用户
# ret = session.query(User).filter(User.username == ‘alex1‘).all()
# print(ret)
# ret = session.query(User).all()
# obj = ret[0]
# print(ret)
# print(obj)
# print(obj.nid)
# print(obj.username)
# print(obj.group_id)

#映射
# ret = session.query(User.username).all()
# print(ret)
# sql = session.query(User,Group).join(Group, isouter=True)
# print(sql)
# ret = session.query(User,Group).join(Group, isouter=True).all()
# print(ret)
# select * from user left join group on user.group_id = group.nid



#原始方法,连表查询
r = session.query(user.username,group.name).join(group,isouter=True).all()
print(r)
#新方式，正向查询
ret = session.query(user).all()
for obj in ret:
    print(obj.nid,obj.username,obj.group_id,obj.group.nid,obj.group.name)

#原始方法
q = session.query(user.username,group.name).join(group,isouter=True).filter(group.name==‘DBA‘).all()
print(q)
#反向查询
obj2 = session.query(group).filter(group.name == ‘DBA‘).first()
print(obj2.nid)
print(obj2.name)
print(obj2.uuu)

#!/usr/bin/env python
#-*- coding:utf-8 -*-
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint, Index
from sqlalchemy.orm import sessionmaker, relationship

engine = create_engine("mysql+pymysql://root:123.com@192.168.11.233:3306/zeng", max_overflow=5)
Base = declarative_base()

####****************定义表************************
class Host(Base):
    __tablename__ = ‘host‘
    nid = Column(Integer, primary_key=True,autoincrement=True)
    hostname = Column(String(32))
    port = Column(String(32))
    ip = Column(String(32))

class HostUser(Base):
    __tablename__ = ‘host_user‘
    nid = Column(Integer, primary_key=True,autoincrement=True)
    username = Column(String(32))

class HostToHostUser(Base):
    __tablename__ = ‘host_to_host_user‘
    nid = Column(Integer, primary_key=True,autoincrement=True)
    host_id = Column(Integer,ForeignKey(‘host.nid‘))
    host_user_id = Column(Integer,ForeignKey(‘host_user.nid‘))
#******************与另外两张表建立关系，可以通过h，u查询************************
    host = relationship("Host",backref=‘h‘)
    host_user = relationship("HostUser",backref = ‘u‘)


# Base.metadata.create_all(engine)
if __name__ == ‘__main__‘:
    Session = sessionmaker(bind=engine)
    session=Session()



    host_obj = session.query(Host).filter(Host.hostname==‘c1‘).first()
    print(host_obj.h)
    for i in host_obj.h:
        print(i.host_user.username)
    # session.commit()
#获取1中所有用户
#     host_obj = session.query(Host).filter(Host.hostname == ‘c1‘).first()
#     print(host_obj)
# #获取id为host_obj.nid的所有数据
#     host_2_host_user = session.query(HostToHostUser.host_user_id).filter(HostToHostUser.host_id == host_obj.nid).all()
#     print(host_2_host_user)
#     r = zip(*host_2_host_user)
#     users = session.query(HostUser.username).filter((HostUser.nid.in_list(r)[0])).all()
#     print(users)
#原始代码
# session.query(HostUser.name).filter(HostUser.nid.in_(session.query(HostToHostUser.host_user_id).filter(HostToHostUser.host_id == session.query(Host.nid).filter(Host.hostname == ‘c1‘))))