1. 程式人生 > 資料庫 >python實現的MySQL增刪改查操作例項小結

python實現的MySQL增刪改查操作例項小結

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()

更多關於Python相關內容感興趣的讀者可檢視本站專題:《Python+MySQL資料庫程式設計入門教程》、《Python常見資料庫操作技巧彙總》、《Python數學運算技巧總結》、《Python資料結構與演算法教程》、《Python函式使用技巧總結》、《Python字串操作技巧彙總》、《Python入門與進階經典教程》及《Python檔案與目錄操作技巧彙總》

希望本文所述對大家Python程式設計有所幫助。