ORM框架SQLAlchemy操作表：

表结构和数据库连接：

1 #!/usr/bin/env python 2 # -*- coding:utf-8 -*- 3 from sqlalchemy.ext.declarative import declarative_base 4 from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint, Index 5 from sqlalchemy.orm import sessionmaker, relationship 6 from sqlalchemy import create_engine 7  8 engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/t1", max_overflow=5) 9 10 Base = declarative_base()11 12 # 创建单表13 class Users(Base):14     __tablename__ = 'users'15     id = Column(Integer, primary_key=True)16     name = Column(String(32))17     extra = Column(String(16))18 19     __table_args__ = (20     UniqueConstraint('id', 'name', name='uix_id_name'),21         Index('ix_id_name', 'name', 'extra'),22     )23 24     def __repr__(self):25         return "%s-%s" %(self.id, self.name)26 27 # 一对多28 class Favor(Base):29     __tablename__ = 'favor'30     nid = Column(Integer, primary_key=True)31     caption = Column(String(50), default='red', unique=True)32 33     def __repr__(self):34         return "%s-%s" %(self.nid, self.caption)35 36 class Person(Base):37     __tablename__ = 'person'38     nid = Column(Integer, primary_key=True)39     name = Column(String(32), index=True, nullable=True)40     favor_id = Column(Integer, ForeignKey("favor.nid"))41     # 与生成表结构无关，仅用于查询方便42     favor = relationship("Favor", backref='pers')43 44 # 多对多45 class ServerToGroup(Base):46     __tablename__ = 'servertogroup'47     nid = Column(Integer, primary_key=True, autoincrement=True)48     server_id = Column(Integer, ForeignKey('server.id'))49     group_id = Column(Integer, ForeignKey('group.id'))50     group = relationship("Group", backref='s2g')51     server = relationship("Server", backref='s2g')52 53 class Group(Base):54     __tablename__ = 'group'55     id = Column(Integer, primary_key=True)56     name = Column(String(64), unique=True, nullable=False)57     port = Column(Integer, default=22)58     # group = relationship('Group',secondary=ServerToGroup,backref='host_list')59 60 61 class Server(Base):62     __tablename__ = 'server'63 64     id = Column(Integer, primary_key=True, autoincrement=True)65     hostname = Column(String(64), unique=True, nullable=False)66 67 68 69 70 def init_db():71     Base.metadata.create_all(engine)72 73 74 def drop_db():75     Base.metadata.drop_all(engine)76 77 78 Session = sessionmaker(bind=engine)79 session = Session()

增：

1 obj = Users(name="alex0", extra='sb')2 session.add(obj)3 session.add_all([4     Users(name="alex1", extra='sb'),5     Users(name="alex2", extra='sb'),6 ])7 session.commit()

查：

1 ret = session.query(Users).all()2 ret = session.query(Users.name, Users.extra).all()3 ret = session.query(Users).filter_by(name='alex').all()4 ret = session.query(Users).filter_by(name='alex').first()5 6 ret = session.query(Users).filter(text("id<:value and name=:name")).params(value=224, name='fred').order_by(User.id).all()7 8 ret = session.query(Users).from_statement(text("SELECT * FROM users where name=:name")).params(name='ed').all()

删：先查后删

1 session.query(Users).filter(Users.id > 2).delete()2 session.commit()

改：先查后改

1 session.query(Users).filter(Users.id > 2).update({
   "name" : "099"})2 session.query(Users).filter(Users.id > 2).update({Users.name: Users.name + "099"}, synchronize_session=False)3 session.query(Users).filter(Users.id > 2).update({
   "num": Users.num + 1}, synchronize_session="evaluate")4 session.commit()

其他：

1 #　条件 2 ret = session.query(Users).filter_by(name='alex').all() 3 ret = session.query(Users).filter(Users.id > 1, Users.name == 'eric').all() 4 ret = session.query(Users).filter(Users.id.between(1, 3), Users.name == 'eric').all() 5 ret = session.query(Users).filter(Users.id.in_([1,3,4])).all() 6 ret = session.query(Users).filter(~Users.id.in_([1,3,4])).all() 7 ret = session.query(Users).filter(Users.id.in_(session.query(Users.id).filter_by(name='eric'))).all() 8 from sqlalchemy import and_, or_ 9 ret = session.query(Users).filter(and_(Users.id > 3, Users.name == 'eric')).all()10 ret = session.query(Users).filter(or_(Users.id < 2, Users.name == 'eric')).all()11 ret = session.query(Users).filter(12     or_(13         Users.id < 2,14         and_(Users.name == 'eric', Users.id > 3),15         Users.extra != ""16     )).all()17 18 19 # 通配符20 ret = session.query(Users).filter(Users.name.like('e%')).all()21 ret = session.query(Users).filter(~Users.name.like('e%')).all()22 23 # 限制24 ret = session.query(Users)[1:2]25 26 # 排序27 ret = session.query(Users).order_by(Users.name.desc()).all()28 ret = session.query(Users).order_by(Users.name.desc(), Users.id.asc()).all()29 30 # 分组31 from sqlalchemy.sql import func32 33 ret = session.query(Users).group_by(Users.extra).all()34 ret = session.query(35     func.max(Users.id),36     func.sum(Users.id),37     func.min(Users.id)).group_by(Users.name).all()38 39 ret = session.query(40     func.max(Users.id),41     func.sum(Users.id),42     func.min(Users.id)).group_by(Users.name).having(func.min(Users.id) >2).all()43 44 # 连表45 46 ret = session.query(Users, Favor).filter(Users.id == Favor.nid).all()47 48 ret = session.query(Person).join(Favor).all()49 50 ret = session.query(Person).join(Favor, isouter=True).all()51 52 53 # 组合54 q1 = session.query(Users.name).filter(Users.id > 2)55 q2 = session.query(Favor.caption).filter(Favor.nid < 2)56 ret = q1.union(q2).all()57 58 q1 = session.query(Users.name).filter(Users.id > 2)59 q2 = session.query(Favor.caption).filter(Favor.nid < 2)60 ret = q1.union_all(q2).all()