本文实例总结了python实现的MySQL增删改查操作。分享给大家供大家参考，具体如下：
代码片段一
连接并执行sql
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#encoding:UTF-8import MySQLdbconn = MySQLdb.Connect( host = '127.0.0.1', port = 3306, user = 'root', passwd='123456', db='imooc', charset='utf8')cursor = conn.cursor()print connprint cursorsql = "select * from user"cursor.execute(sql) #执行 |
取数据
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print cursor.rowcount#取数据#fetchone()获取一条数据#fetchany(3)获取多条#fetchall()#获取客户缓冲区的所有数据# rs = cursor.fetchone()# print rs## rs = cursor.fetchmany(2)# print rs## rs = cursor.fetchall()# print rs# rs = cursor.fetchall()# for row in rs:# print "userid=%s,username=%s" % row |
更新数据库
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# sql_insert = "insert into user(userid,username) values(10,'name10')"# sql_update = "update user set username='name91' where userid=9"# sql_delete = "delete from user where userid<3"# cursor.execute(sql_insert)# cursor.execute(sql_update)# cursor.execute(sql_delete)# #执行完后提交# conn.commit()# #发生异常时回滚# try:# sql_insert = "insert into user(userid,username) values(10,'name10')"# sql_update = "update user set username='name91' where userid=9"# sql_delete = "delete from user where userid<3"# cursor.execute(sql_insert)# cursor.execute(sql_update)# cursor.execute(sql_delete)# conn.commit()# except Exception as e:# print e# conn.rollback()cursor.close()conn.close() |
代码片段2 银行实例
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#coding:UTF-8import sysimport MySQLdbclass TransferMoney(object): def __init__(self,conn): self.conn = conn def tranfer(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() raise e def check_acct_available(self, acctid): cursor = self.conn.cursor() try: sql = "select * from account where acctid=%s"%acctid cursor.execute(sql) rs = cursor.fetchall() if len(rs)!=1: raise Exception("账号%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) cursor.execute(sql) print "has_enough_money:"+sql rs = cursor.fetchall() if len(rs) != 1: raise Exception("账号%s没有足够的钱" % 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) cursor.execute(sql) print "reduce_money:"+sql if cursor.rowcount != 1: raise Exception("账号%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) cursor.execute(sql) print "reduce_money:" + sql if cursor.rowcount != 1: raise Exception("账号%s加款失败" % acctid) finally: cursor.close()if __name__ == "__main__": source_acctid = sys.argv[1] target_acctid = sys.argv[2] money = sys.argv[3] conn = MySQLdb.Connect( host='127.0.0.1', port=3306, user='root', passwd='123456', db='imooc', charset='utf8' ) tr_money = TransferMoney(conn) try: tr_money.tranfer(source_acctid,target_acctid,money) except Exception as e: print "出现问题了" + str(e) finally: conn.close() |
希望本文所述对大家Python程序设计有所帮助。
原文链接：https://blog.csdn.net/Tangzongyu123/article/details/76793805
