pymysql
pymysql是Python中操作MySQL的模块，其使用方法和python2.7的MySQLdb几乎相同。
一、下载安装：
pip3 install pymysql
二、使用
1、执行SQL
#!/usr/bin/env python# -*- coding:utf-8 -*-import pymysql # 创建连接conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', passwd='123', db='t1')# 创建游标cursor = conn.cursor() # 执行SQL，并返回收影响行数effect_row = cursor.execute("update hosts set host = '1.1.1.2'") # 执行SQL，并返回受影响行数#effect_row = cursor.execute("update hosts set host = '1.1.1.2' where nid > %s", (1,)) # 执行SQL，并返回受影响行数#effect_row = cursor.executemany("insert into hosts(host,color_id)values(%s,%s)", [("1.1.1.11",1),("1.1.1.11",2)]) # 提交，不然无法保存新建或者修改的数据conn.commit() # 关闭游标cursor.close()# 关闭连接conn.close() 2、获取新创建数据自增ID
#!/usr/bin/env python# -*- coding:utf-8 -*-import pymysql conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', passwd='123', db='t1')cursor = conn.cursor()cursor.executemany("insert into hosts(host,color_id)values(%s,%s)", [("1.1.1.11",1),("1.1.1.11",2)])conn.commit()cursor.close()conn.close() # 获取最新自增IDnew_id = cursor.lastrowid 3、获取查询数据
#!/usr/bin/env python# -*- coding:utf-8 -*-import pymysql conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', passwd='123', db='t1')cursor = conn.cursor()cursor.execute("select * from hosts") # 获取第一行数据row_1 = cursor.fetchone() # 获取前n行数据# row_2 = cursor.fetchmany(3)# 获取所有数据# row_3 = cursor.fetchall() conn.commit()cursor.close()conn.close() 注：在fetch数据时按照顺序进行，可以使用cursor.scroll(num,mode)来移动游标位置，如：
cursor.scroll(1,mode='relative') # 相对当前位置移动
cursor.scroll(2,mode='absolute') # 相对绝对位置移动
4、fetch数据类型
关于默认获取的数据是元祖类型，如果想要或者字典类型的数据，即：
#!/usr/bin/env python# -*- coding:utf-8 -*-import pymysql conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', passwd='123', db='t1') # 游标设置为字典类型cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)r = cursor.execute("select * from tb1") result = cursor.fetchone() conn.commit()cursor.close()conn.close() SQLAchemy
SQLAlchemy是编程语言下的一款ORM框架，该框架建立在数据库API之上，使用关系对象映射进行数据库操作，简言之便是：将对象转换成SQL，然后使用数据API执行SQL并获取执行结果。
SQLAlchemy本身无法操作数据库，其必须以来pymsql等第三方插件，Dialect用于和数据API进行交流，根据配置文件的不同调用不同的数据库API，从而实现对数据库的操作，如：
MySQL-Python mysql+mysqldb://: @ [: ]/ pymysql mysql+pymysql:// : @ / [? ] MySQL-Connector mysql+mysqlconnector:// : @ [: ]/ cx_Oracle oracle+cx_oracle://user:pass@host:port/dbname[?key=value&key=value...] 更多详见：http://docs.sqlalchemy.org/en/latest/dialects/index.html
一、底层处理
使用 Engine/ConnectionPooling/Dialect 进行数据库操作，Engine使用ConnectionPooling连接数据库，然后再通过Dialect执行SQL语句。
#!/usr/bin/env python# -*- coding:utf-8 -*-from sqlalchemy import create_engine engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/t1", max_overflow=5) # 执行SQL# cur = engine.execute(# "INSERT INTO hosts (host, color_id) VALUES ('1.1.1.22', 3)"# ) # 新插入行自增ID# cur.lastrowid # 执行SQL# cur = engine.execute(# "INSERT INTO hosts (host, color_id) VALUES(%s, %s)",[('1.1.1.22', 3),('1.1.1.221', 3),]# ) # 执行SQL# cur = engine.execute(# "INSERT INTO hosts (host, color_id) VALUES (%(host)s, %(color_id)s)",# host='1.1.1.99', color_id=3# ) # 执行SQL# cur = engine.execute('select * from hosts')# 获取第一行数据# cur.fetchone()# 获取第n行数据# cur.fetchmany(3)# 获取所有数据# cur.fetchall() #!/usr/bin/env python# -*- coding:utf-8 -*-from sqlalchemy import create_engineengine = create_engine("mysql+mysqldb://root:123@127.0.0.1:3306/s11", max_overflow=5)# 事务操作with engine.begin() as conn: conn.execute("insert into table (x, y, z) values (1, 2, 3)") conn.execute("my_special_procedure(5)") conn = engine.connect()# 事务操作 with conn.begin(): conn.execute("some statement", {'x':5, 'y':10}) 注：查看数据库连接：show status like 'Threads%';
二、ORM功能使用
使用 ORM/Schema Type/SQL Expression Language/Engine/ConnectionPooling/Dialect 所有组件对数据进行操作。根据类创建对象，对象转换成SQL，执行SQL。
1、创建表
#!/usr/bin/env python# -*- coding:utf-8 -*-from sqlalchemy.ext.declarative import declarative_basefrom sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint, Indexfrom sqlalchemy.orm import sessionmaker, relationshipfrom sqlalchemy import create_engineengine = 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) # 定义在Server中的关系(就是利用第三张表将两张表联系起来，这里只需写这么一条即可) # group = relationship('Group', secondary=ServerToGroup.__table__, backref='ggg')class ServerToGroup(Base): __tablename__ = 'servertogroup' nid = Column(Integer, primary_key=True, autoincrement=True) # 定义外键 server_id = Column(Integer, ForeignKey('server.id')) group_id = Column(Integer, ForeignKey('group.id')) # 定义关系（定义在关系表里面，也可以定义在其他表的类里，但写法有区别） group = relationship('Group', backref='ggg') server = relationship('Server', backref='sss')def init_db(): Base.metadata.create_all(engine) # 寻找Base的所有子类，按照子类的结构在数据库中生成对应的数据表信息def drop_db(): Base.metadata.drop_all(engine) 2、操作表
# 创建表的基础之上Session = sessionmaker(bind=engine)session = Session()
增 obj = Users(name="alex0", extra='sb')session.add(obj)session.add_all([ Users(name="alex1", extra='sb'), Users(name="alex2", extra='sb'),])session.commit() 删 session.query(Users).filter(Users.id > 2).delete()session.commit() 改 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()查 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() 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 funcret = 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() # 左连接，无右连接# 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()更多功能参见文档，下载PDF |
表结构操作联系（看看就行）
#!/usr/bin/env python# -*- coding:utf-8 -*-from sqlalchemy import create_engine,and_,or_,func,Tablefrom sqlalchemy.ext.declarative import declarative_basefrom sqlalchemy import Column, Integer, String,ForeignKey,UniqueConstraint,DateTimefrom sqlalchemy.orm import sessionmaker,relationshipBase = declarative_base() #生成一个SqlORM 基类# 服务器账号和组# HostUser2Group = Table('hostuser_2_group',Base.metadata,# Column('hostuser_id',ForeignKey('host_user.id'),primary_key=True),# Column('group_id',ForeignKey('group.id'),primary_key=True),# )# 用户和组关系表，用户可以属于多个组，一个组可以有多个人UserProfile2Group = Table('userprofile_2_group',Base.metadata, Column('userprofile_id',ForeignKey('user_profile.id'),primary_key=True), Column('group_id',ForeignKey('group.id'),primary_key=True),)# 程序登陆用户和服务器账户，一个人可以有多个服务器账号，一个服务器账号可以给多个人用UserProfile2HostUser= Table('userprofile_2_hostuser',Base.metadata, Column('userprofile_id',ForeignKey('user_profile.id'),primary_key=True), Column('hostuser_id',ForeignKey('host_user.id'),primary_key=True),)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) def __repr__(self): return " " %(self.id, self.hostname, self.ip_addr)class HostUser(Base): __tablename__ = 'host_user' id = Column(Integer,primary_key=True) AuthTypes = [ (u'ssh-passwd',u'SSH/Password'), (u'ssh-key',u'SSH/KEY'), ] # auth_type = Column(ChoiceType(AuthTypes)) auth_type = Column(String(64)) username = Column(String(64),unique=True,nullable=False) password = Column(String(255)) host_id = Column(Integer,ForeignKey('host.id')) # groups = relationship('Group', # secondary=HostUser2Group, # backref='host_list') __table_args__ = (UniqueConstraint('host_id','username', name='_host_username_uc'),) def __repr__(self): return " " %(self.id,self.username)class Group(Base): __tablename__ = 'group' id = Column(Integer,primary_key=True) name = Column(String(64),unique=True,nullable=False) def __repr__(self): return " " %(self.id,self.name)class UserProfile(Base): __tablename__ = 'user_profile' id = Column(Integer,primary_key=True) username = Column(String(64),unique=True,nullable=False) password = Column(String(255),nullable=False) # host_list = relationship('HostUser', # secondary=UserProfile2HostUser, # backref='userprofiles') # groups = relationship('Group', # secondary=UserProfile2Group, # backref='userprofiles') def __repr__(self): return " " %(self.id,self.username)class AuditLog(Base): __tablename__ = 'audit_log' id = Column(Integer,primary_key=True) userprofile_id = Column(Integer,ForeignKey('user_profile.id')) hostuser_id = Column(Integer,ForeignKey('host_user.id')) action_choices2 = [ (u'cmd',u'CMD'), (u'login',u'Login'), (u'logout',u'Logout'), ] action_type = Column(ChoiceType(action_choices2)) #action_type = Column(String(64)) cmd = Column(String(255)) date = Column(DateTime) # user_profile = relationship("UserProfile") #bind_host = relationship("BindHost")engine = create_engine("mysql+pymsql://root:123@localhost:3306/stupid_jumpserver",echo=False)Base.metadata.create_all(engine) #创建所有表结构