Python学习笔记 - MySql的使用，,一、安装MySql模

Python学习笔记 - MySql的使用，,一、安装MySql模

一、安装MySql模块

Python2.X

pip install MySQLdb

Python3.X

pip install pymysql

二、数据库连接接口

由于Python统一了数据库连接的接口，所以 pymysql 和 MySQLdb 在使用方式上是类似的：

pymysql.Connect()参数说明host(str):      MySQL服务器地址port(int):      MySQL服务器端口号user(str):      用户名passwd(str):    密码db(str):        数据库名称charset(str):   连接编码connection对象支持的方法cursor()        使用该连接创建并返回游标commit()        提交当前事务rollback()      回滚当前事务close()         关闭连接cursor对象支持的方法execute(op)     执行一个数据库的查询命令fetchone()      取得结果集的下一行fetchmany(size) 获取结果集的下几行fetchall()      获取结果集中的所有行rowcount()      返回数据条数或影响行数close()         关闭游标对象

三、范例

MySql脚本

-- ------------------------------ Table structure for account-- ----------------------------DROP TABLE IF EXISTS `account`;CREATE TABLE `account`  (  `acctid` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,  `name` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,  `money` decimal(50, 0) NULL DEFAULT NULL) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;-- ------------------------------ Records of account-- ----------------------------INSERT INTO `account` VALUES (‘1‘, ‘张三‘, 50);INSERT INTO `account` VALUES (‘2‘, ‘李四‘, 150);

Python程序

#   coding:utf8import sysimport pymysqlclass TransferMoney(object):    def __init__(self, conn):        self.conn = conn    def check_acct_available(self, acctid):        cursor = self.conn.cursor()        try:            sql = "select * from account where acctid=‘%s‘" % acctid            print("check_acct_available:" + sql)            cursor.execute(sql)            rs = cursor.fetchall()            if len(rs) != 1:                raise Exception("帐号%s不存在" % acctid)        finally:            cursor.close()    def has_enough_money(self, acctid, money):        cursor = self.conn.cursor()        try:            sql = "select * from account where acctid=‘%s‘ and money>%s" % (                acctid, money)            print("has_enough_money:" + sql)            cursor.execute(sql)            rs = cursor.fetchall()            if len(rs) != 1:                raise Exception("帐号%s没有足够的金额" % acctid)        finally:            cursor.close()    def reduce_money(self, acctid, money):        cursor = self.conn.cursor()        try:            sql = "update account set money=money-%s where acctid=‘%s‘ " % (                money, acctid)            print("reduce_money:" + sql)            cursor.execute(sql)            if cursor.rowcount != 1:                raise Exception("帐号%s减款失败" % acctid)        finally:            cursor.close()    def add_money(self, acctid, money):        cursor = self.conn.cursor()        try:            sql = "update account set money=money+%s where acctid=‘%s‘ " % (                money, acctid)            print("add_money:" + sql)            cursor.execute(sql)            if cursor.rowcount != 1:                raise Exception("帐号%s加款失败" % acctid)        finally:            cursor.close()    def transfer(self, source_acctid, target_acctid, money):        try:            self.check_acct_available(source_acctid)            self.check_acct_available(target_acctid)            self.has_enough_money(source_acctid, money)            self.reduce_money(source_acctid, money)            self.add_money(target_acctid, money)            self.conn.commit()        except Exception as e:            self.conn.rollback()            print("transfer出现异常：" + str(e))            raise edef main():    source_acctid = sys.argv[1]    print("转出帐号=" + source_acctid)    target_acctid = sys.argv[2]    print("转入帐号=" + target_acctid)    money = sys.argv[3]    print("金额=" + money)    # 连接数据库    conn = pymysql.Connect(        host=‘localhost‘,        port=3306,        user=‘root‘,        passwd=‘root‘,        db=‘OtkDb‘,        charset=‘utf8‘)    tr_money = TransferMoney(conn)    try:        tr_money.transfer(source_acctid, target_acctid, money)    except Exception as e:        print("main出现异常：" + str(e))    finally:        conn.close()if __name__ == ‘__main__‘:    main()

四、运行效果

PS H:\web\Python> & python h:\web\Python\01.MySql\db.py 1 2 50转出帐号=1转入帐号=2金额=50check_acct_available:select * from account where acctid=‘1‘check_acct_available:select * from account where acctid=‘2‘has_enough_money:select * from account where acctid=‘1‘ and money>50reduce_money:update account set money=money-50 where acctid=‘1‘add_money:update account set money=money+50 where acctid=‘2‘

PS H:\web\Python> & python h:\web\Python\01.MySql\db.py 1 2 50转出帐号=1转入帐号=2金额=50check_acct_available:select * from account where acctid=‘1‘check_acct_available:select * from account where acctid=‘2‘has_enough_money:select * from account where acctid=‘1‘ and money>50transfer出现异常：帐号1没有足够的金额main出现异常：帐号1没有足够的金额

参考：

http://www.cnblogs.com/woider/p/5926744.html

Python学习笔记 - MySql的使用