本文實例總結了python實現的MySQL增刪改查操作。分享給大家供大家參考,具體如下:
代碼片段一
連接并執行sql
#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) #執行
取數據
print cursor.rowcount#取數據#fetchone()獲取一條數據#fetchany(3)獲取多條#fetchall()#獲取客戶緩沖區的所有數據# 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
更新數據庫
# 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)# #執行完后提交# conn.commit()# #發生異常時回滾# 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()
代碼片段2 銀行實例
#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("賬號%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("賬號%s沒有足夠的錢" % 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("賬號%s減款失敗" % 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("賬號%s加款失敗" % 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 "出現問題了" + str(e) finally: conn.close()希望本文所述對大家Python程序設計有所幫助。
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