python實現的MySQL增刪改查操作例項小結
阿新 • • 發佈:2020-01-09
本文例項總結了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:
程式碼片段一
連線並執行sql
#encoding:UTF-8 import MySQLdb conn = MySQLdb.Connect( host = '127.0.0.1',port = 3306,user = 'root',passwd='123456',db='imooc',charset='utf8' ) cursor = conn.cursor() print conn print cursor sql = "select * from user" cursor.execute(sql) #執行
取資料
print cursor.rowcount #取資料 #fetchone()獲取一條資料 #fetchany(3)獲取多條 #fetchall()#獲取客戶緩衝區的所有資料 # 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
更新資料庫
# 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) # #執行完後提交 # conn.commit() # #發生異常時回滾 # try: # sql_insert = "insert into user(userid,'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()
程式碼片段2 銀行例項
#coding:UTF-8 import sys import MySQLdb class 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,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,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',charset='utf8' ) tr_money = TransferMoney(conn) try: tr_money.tranfer(source_acctid,money) except Exception as e: print "出現問題了" + str(e) finally: conn.close()
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希望本文所述對大家Python程式設計有所幫助。