• SQLAlchemy基础操作四


    SQLAlchemy 剩下内容之所有
    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    import time
    import threading
    
    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
    from sqlalchemy.sql import text
    from sqlalchemy.engine.result import ResultProxy
    from db import Users, Hosts
    
    engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/s6", max_overflow=0, pool_size=5)
    Session = sessionmaker(bind=engine)
    
    session = Session()
    
    # 查询
    # cursor = session.execute('select * from users')
    # result = cursor.fetchall()
    
    # 添加
    cursor = session.execute('insert into users(name) values(:value)',params={"value":'wupeiqi'})
    session.commit()
    print(cursor.lastrowid)
    
    session.close()
    原生SQL语句
    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    import time
    import threading
    
    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
    from sqlalchemy.sql import text
    from sqlalchemy.engine.result import ResultProxy
    from db import Users, Hosts, Hobby, Person
    
    engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/s6?charset=utf8", max_overflow=0, pool_size=5)
    Session = sessionmaker(bind=engine)
    session = Session()
    # 添加
    """
    session.add_all([
        Hobby(caption='乒乓球'),
        Hobby(caption='羽毛球'),
        Person(name='张三', hobby_id=3),
        Person(name='李四', hobby_id=4),
    ])
    
    person = Person(name='张九', hobby=Hobby(caption='姑娘'))
    session.add(person)
    
    hb = Hobby(caption='人妖')
    hb.pers = [Person(name='文飞'), Person(name='博雅')]
    session.add(hb)
    
    session.commit()
    """
    
    # 使用relationship正向查询
    """
    v = session.query(Person).first()
    print(v.name)
    print(v.hobby.caption)
    """
    
    # 使用relationship反向查询
    """
    v = session.query(Hobby).first()
    print(v.caption)
    print(v.pers)
    """
    
    session.close()
    基于relationship操作ForeignKey
    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    import time
    import threading
    
    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
    from sqlalchemy.sql import text
    from sqlalchemy.engine.result import ResultProxy
    from db import Users, Hosts, Hobby, Person, Group, Server, Server2Group
    
    engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/s6?charset=utf8", max_overflow=0, pool_size=5)
    Session = sessionmaker(bind=engine)
    session = Session()
    # 添加
    """
    session.add_all([
        Server(hostname='c1.com'),
        Server(hostname='c2.com'),
        Group(name='A组'),
        Group(name='B组'),
    ])
    session.commit()
    
    s2g = Server2Group(server_id=1, group_id=1)
    session.add(s2g)
    session.commit()
    
    
    gp = Group(name='C组')
    gp.servers = [Server(hostname='c3.com'),Server(hostname='c4.com')]
    session.add(gp)
    session.commit()
    
    
    ser = Server(hostname='c6.com')
    ser.groups = [Group(name='F组'),Group(name='G组')]
    session.add(ser)
    session.commit()
    """
    
    
    # 使用relationship正向查询
    """
    v = session.query(Group).first()
    print(v.name)
    print(v.servers)
    """
    
    # 使用relationship反向查询
    """
    v = session.query(Server).first()
    print(v.hostname)
    print(v.groups)
    """
    
    
    session.close()
    基于relationship操作m2m
    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    import time
    import threading
    
    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
    from sqlalchemy.sql import text, func
    from sqlalchemy.engine.result import ResultProxy
    from db import Users, Hosts, Hobby, Person, Group, Server, Server2Group
    
    engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/s6?charset=utf8", max_overflow=0, pool_size=5)
    Session = sessionmaker(bind=engine)
    session = Session()
    
    # 关联子查询
    subqry = session.query(func.count(Server.id).label("sid")).filter(Server.id == Group.id).correlate(Group).as_scalar()
    result = session.query(Group.name, subqry)
    """
    SELECT `group`.name AS group_name, (SELECT count(server.id) AS sid 
    FROM server 
    WHERE server.id = `group`.id) AS anon_1 
    FROM `group`
    """
    
    
    # 原生SQL
    """
    # 查询
    cursor = session.execute('select * from users')
    result = cursor.fetchall()
    
    # 添加
    cursor = session.execute('insert into users(name) values(:value)',params={"value":'wupeiqi'})
    session.commit()
    print(cursor.lastrowid)
    """
    
    session.close()
    其他
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
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  • 原文地址:https://www.cnblogs.com/wanghaohao/p/8276434.html
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