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  • day40--mysql step4 SQLAlchemy

    1、unique = True 表示启动唯一索

    2、有add 必须有commit这样数据才会提交

    3、ORM功能

    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    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:123@127.0.0.1:3306/t1", max_overflow=5)
     
    Base = declarative_base()
     
    # 创建单表
    class Users(Base):
        __tablename__ = 'users'
        id = Column(Integer, primary_key=True)
        name = Column(String(32))
        extra = Column(String(16))
     
        __table_args__ = (
        UniqueConstraint('id', 'name', name='uix_id_name'),
            Index('ix_id_name', 'name', 'extra'),
        )
     
     
    # 一对多
    class Favor(Base):
        __tablename__ = 'favor'
        nid = Column(Integer, primary_key=True)
        caption = Column(String(50), default='red', unique=True)
     
     
    class Person(Base):
        __tablename__ = 'person'
        nid = Column(Integer, primary_key=True)
        name = Column(String(32), index=True, nullable=True)
        favor_id = Column(Integer, ForeignKey("favor.nid"))
     
     
    # 多对多
    class Group(Base):
        __tablename__ = 'group'
        id = Column(Integer, primary_key=True)
        name = Column(String(64), unique=True, nullable=False)
        port = Column(Integer, default=22)
     
     
    class Server(Base):
        __tablename__ = 'server'
     
        id = Column(Integer, primary_key=True, autoincrement=True)
        hostname = Column(String(64), unique=True, nullable=False)
     
     
    class ServerToGroup(Base):
        __tablename__ = 'servertogroup'
        nid = Column(Integer, primary_key=True, autoincrement=True)
        server_id = Column(Integer, ForeignKey('server.id'))
        group_id = Column(Integer, ForeignKey('group.id'))
     
     
    def init_db():
        Base.metadata.create_all(engine)
     
     
    def drop_db():
        Base.metadata.drop_all(engine)
    建表
    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    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:123@127.0.0.1:3306/t1", max_overflow=5)
    
    Base = declarative_base()
    
    # 创建单表
    class Users(Base):
        __tablename__ = 'users'
        id = Column(Integer, primary_key=True)
        name = Column(String(32))
        extra = Column(String(16))
    
        __table_args__ = (
        UniqueConstraint('id', 'name', name='uix_id_name'),
            Index('ix_id_name', 'name', 'extra'),
        )
    
        def __repr__(self):
            return "%s-%s" %(self.id, self.name)
    
    # 一对多
    class Favor(Base):
        __tablename__ = 'favor'
        nid = Column(Integer, primary_key=True)
        caption = Column(String(50), default='red', unique=True)
    
        def __repr__(self):
            return "%s-%s" %(self.nid, self.caption)
    
    class Person(Base):
        __tablename__ = 'person'
        nid = Column(Integer, primary_key=True)
        name = Column(String(32), index=True, nullable=True)
        favor_id = Column(Integer, ForeignKey("favor.nid"))
        # 与生成表结构无关,仅用于查询方便
        favor = relationship("Favor", backref='pers')
    
    # 多对多
    class ServerToGroup(Base):
        __tablename__ = 'servertogroup'
        nid = Column(Integer, primary_key=True, autoincrement=True)
        server_id = Column(Integer, ForeignKey('server.id'))
        group_id = Column(Integer, ForeignKey('group.id'))
        group = relationship("Group", backref='s2g')
        server = relationship("Server", backref='s2g')
    
    class Group(Base):
        __tablename__ = 'group'
        id = Column(Integer, primary_key=True)
        name = Column(String(64), unique=True, nullable=False)
        port = Column(Integer, default=22)
        # group = relationship('Group',secondary=ServerToGroup,backref='host_list')
    
    
    class Server(Base):
        __tablename__ = 'server'
    
        id = Column(Integer, primary_key=True, autoincrement=True)
        hostname = Column(String(64), unique=True, nullable=False)
    
    
    
    
    def init_db():
        Base.metadata.create_all(engine)
    
    
    def drop_db():
        Base.metadata.drop_all(engine)
    
    
    Session = sessionmaker(bind=engine)
    session = Session()
    
    表结构 + 数据库连接
    连接db
    #
    obj = Users(name="alex0", extra='sb')
    session.add(obj)
    session.add_all([
        Users(name="alex1", extra='sb'),
        Users(name="alex2", extra='sb'),
    ])
    session.commit()
    #
    session.query(Users).filter(Users.id > 2).delete()
    session.commit()
    #
    session.query(Users).filter(Users.id > 2).update({"name" : "099"})
    session.query(Users).filter(Users.id > 2).update({Users.name: Users.name + "099"}, synchronize_session=False)
    session.query(Users).filter(Users.id > 2).update({"num": Users.num + 1}, synchronize_session="evaluate")
    session.commit()
    #
    ret = session.query(Users).all()
    ret = session.query(Users.name, Users.extra).all()
    ret = session.query(Users).filter_by(name='alex').all()
    ret = session.query(Users).filter_by(name='alex').first()
    
    ret = session.query(Users).filter(text("id<:value and name=:name")).params(value=224, name='fred').order_by(User.id).all()
    
    ret = session.query(Users).from_statement(text("SELECT * FROM users where name=:name")).params(name='ed').all()
    #其他
    # 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()
    
    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(Users.name).filter(Users.id > 2)
    q2 = session.query(Favor.caption).filter(Favor.nid < 2)
    ret = q1.union_all(q2).all()
    数据库操作

    条件用 filter单值用filter_by

    4、示例代码

    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    #coding:utf8
    import sqlalchemy
    from sqlalchemy import create_engine
    from sqlalchemy.ext.declarative import declarative_base
    from sqlalchemy import Column, Integer, String
    from sqlalchemy.orm import sessionmaker
    print(sqlalchemy.__version__)
    
    
    engine = create_engine('mysql+pymysql://sysadmin:password01!@10.10.8.12:3306/q2')
    
    Base = declarative_base()#生成一个SQLORM基类
    
    class User(Base):
        __tablename__ = 'sqlalchemydemo'
    
        id = Column(Integer, primary_key=True, autoincrement=True)
        name = Column(String(40))
        fullname = Column(String(40))
        password = Column(String(40))
    
        def __repr__(self):
           return "<User(name='%s', fullname='%s', password='%s')>" % (
                                self.name, self.fullname, self.password)
    
    Base.metadata.create_all(engine)  #创建所有表结构
    # Base.metadata.drop_all(engine)  # 删除所有表
    # ed_user = User(name='xiaoyu', fullname='Xiaoyu Liu', password='123')
    # print(ed_user)
    # #这两行触发sessionmaker类下的__call__方法,return得到 Session实例,赋给变量session,所以session可以调用Session类下的add,add_all等方法
    MySession = sessionmaker(bind=engine)
    session = MySession()
    
    # session.add(ed_user)    ##添加数据
    # our_user = session.query(User).filter_by(name='ed').first()
    # SELECT * FROM users WHERE name="ed" LIMIT 1;
    # session.add_all([
    #     User(name='alex', fullname='Alex Li', password='456'),
    #     User(name='alex', fullname='Alex old', password='789'),
    #     User(name='peiqi', fullname='Peiqi Wu', password='sxsxsx')])
    #
    # session.commit()
    
    #print(">>>",session.query(User).filter_by(name='ed').first())
    # print(session.query(User).all())  #表内容
    
    # for row in session.query(User).order_by(User.id):
    #      print(row)
    # for row in session.query(User).filter(User.name.in_(['alex', 'wendy', 'jack'])):#这里的名字是完全匹配
    #     print(row)
    # for row in session.query(User).filter(~User.name.in_(['ed', 'wendy', 'jack'])):
    #     print(row)
    # print(session.query(User).filter(User.name == 'ed').count())
    from sqlalchemy import and_, or_
    
    # for row in session.query(User).filter(and_(User.name == 'ed', User.fullname == 'Ed Jones')):
    #     print(row)
    for row in session.query(User).filter(or_(User.name == 'ed', User.fullname == 'wendy')):
        print(row)
    lone
    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    
    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://sysadmin:password01!@10.10.8.12:3306/q2')
    
    Base = declarative_base()
    
    class Son(Base):
        __tablename__ = 'son'
        id = Column(Integer, primary_key=True)
        name = Column(String(32))
        age = Column(String(16))
    
        father_id = Column(Integer, ForeignKey('father.id'))
        # father = relationship('Father')
    
        # __table_args__ = (
        #     UniqueConstraint('id', 'name', name='uix_id_name'),
        #     Index('ix_id_name', 'name', 'extra'),
        # )
        #
    
    class Father(Base):
        __tablename__ = 'father'
    
        id = Column(Integer, primary_key=True)
        name = Column(String(32))
        age = Column(String(16))
        son = relationship('Son', backref = 'father')
    
    
    Base.metadata.create_all(engine)
    
    Session = sessionmaker(bind=engine)
    session = Session()
    
    
    # ret3 = session.query(Father).filter_by(id=1).all()
    # ret4 = session.query(Father).filter_by(id=4).first()
    # for ii in ret4.son:
    #     print(ii.name)
    
    # s1 = session.query(Son).filter_by(id=1).first()
    # print(s1.father.name,s1.name)
    
    ret4 = session.query(Father).filter_by(id=4).first()
    w4 = Son(name = 'little alvin4',age = 5)
    ret4.son.append(w4)
    session.add(ret4)
    session.commit()
    
    # print(ret3)
    # for i in ret3:
    #     print(i.name)
    
    #
    # ret1 = session.query(Father.name.label('kkk'), Son.name.label('ppp')).join(Son)
    #
    # ret = session.query(Father.name.label('kkk'), Son.name.label('ppp')).join(Son).all()
    # print(ret1)
    # print(ret)
    #
    # print(len(ret))
    # for ii in ret:
    #     print(ii)
    # # f1 = Father(name='alvin4', age=50)
    # w1 = Son(name='little alvin1', age=4, father_id = 2)
    # w2 = Son(name='little alvin2', age=5, father_id = 2)
    # #
    # # f1.son = [w1, w2]
    # # session.add(f1)
    #
    # session.add_all([w1,w2])
    # session.commit()
    one2many
    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    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://sysadmin:password01!@10.10.8.12:3306/q2?charset=utf8')
    Base = declarative_base()
    
    class Men_to_Wemon1(Base):
        __tablename__ = 'men_to_wemon1'
        nid = Column(Integer, primary_key=True)
        men_id = Column(Integer, ForeignKey('men1.id'))
        women_id = Column(Integer, ForeignKey('women1.id'))
    
    class Men1(Base):
        __tablename__ = 'men1'
        id = Column(Integer, primary_key=True)
        name = Column(String(32))
        age= Column(String(16))
    
    class Women1(Base):
        __tablename__ ='women1'
        id = Column(Integer, primary_key=True)
        name = Column(String(32))
        age= Column(String(16))
        bf=relationship("Men1",secondary=Men_to_Wemon1.__table__,backref='gf')
    
    Base.metadata.create_all(engine)
    #
    Session = sessionmaker(bind=engine)
    session = Session()
    #
    # m1=Men1(name='alex',age=18)
    # m2=Men1(name='wusir',age=18)
    # w1=Women1(name='如花',age=40)
    # w2=Women1(name='铁锤',age=45)
    
    # t1 = Men_to_Wemon1(men_id=1,women_id=2)
    
    m1 = session.query(Men1).filter_by(id = 2).first()
    w1 = session.query(Women1).all()
    m1.gf=w1
    # m1.gf=[w1,w2]
    # w1.bf=[m1,m2]
    session.add_all([m1,])
    # session.add_all([m1,m2,w1,w2])
    # session.add(t1)
    session.commit()
    many2many
    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    
    from sqlalchemy import create_engine, and_, or_, func, Table
    from sqlalchemy.ext.declarative import declarative_base
    from sqlalchemy import Column, Integer, String, ForeignKey
    from  sqlalchemy.orm import sessionmaker, relationship
    
    engine = create_engine('mysql+pymysql://sysadmin:password01!@10.10.8.12:3306/q2?charset=utf8')
    
    Base = declarative_base()  # 生成一个SqlORM 基类
    
    
    class HostToGroup(Base):
        __tablename__ = 'host_2_group'
        nid = Column(Integer, primary_key=True)
        host_id = Column(Integer, ForeignKey("host.id"))
        group_id = Column(Integer, ForeignKey("group.id"))
    
    
    class Host(Base):
        __tablename__ = 'host'
    
        id = Column(Integer, primary_key=True, autoincrement=True)
        hostname = Column(String(64), unique=True, nullable=False)
        ip_addr = Column(String(128), unique=True, nullable=False)
        port = Column(Integer, default=22)
        group = relationship('Group',
                             secondary=HostToGroup.__table__,
                             backref='host_list')
    
        # group =relationship("Group",back_populates='host_list')
        def __repr__(self):
            return "<id=%s,hostname=%s, ip_addr=%s>" % (self.id,
                                                        self.hostname,
                                                        self.ip_addr)
    
    
    class Group(Base):
        __tablename__ = 'group'
        id = Column(Integer, primary_key=True)
        name = Column(String(64), unique=True, nullable=False)
    
        def __repr__(self):
            return "<id=%s,name=%s>" % (self.id, self.name)
    
    
    Base.metadata.create_all(engine)  # 创建所有表结构
    
    if __name__ == '__main__':
        SessionCls = sessionmaker(bind=engine)
        session = SessionCls()
        #
        # g1 = Group(name='g1')
        # g2 = Group(name='g2')
        # g3 = Group(name='g3')
        # g4 = Group(name='g4')
        # session.add_all([g1,g2,g3,g4])
        # h1 = Host(hostname='h1',ip_addr='192.168.1.56')
        # h2 = Host(hostname='h2',ip_addr='192.168.1.57',port=10000)
        # h3 = Host(hostname='ubuntu',ip_addr='192.168.1.58',port=10000)
        #
        # h1.group=[g2,g4]
        # session.add_all([h1,h2,h3])
        # session.commit()
    
    
        # groups = session.query(Group).all()
        # h2 = session.query(Host).filter(Host.hostname=='h2').first()
        # h2.group = groups[:-1]
        # print("===========>",h2.group)
    
    
    
        g4 = session.query(Group).filter(Group.name=='g4').first()
        print(g4)
        obj1 = session.query(Host).filter(Host.hostname=='h1').update({'port':444})
        obj2 = session.query(Host).filter(Host.hostname=='h1').first()
    
        # g4.host_list.append(obj2)
        obj2.group.append(g4)
    
        #
        # obj2= session.query(Host).filter(Host.hostname=='h1').first()
        # print("h1:",obj2.group)
        # print("g:",g4.host_list )
    
    
    
    
    
        session.commit()
    many2many2
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  • 原文地址:https://www.cnblogs.com/workherd/p/8732357.html
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