Python操作MySQL数据库：增删改查与事务处理实战

Felix

发布时间：2026-10-13 | 2人浏览过

原创

本文详细总结了使用Python进行MySQL数据库操作的核心方法，涵盖连接建立、SQL执行、数据获取及更新删除等基础功能。通过银行转账实例演示了完整的事务控制流程，包括数据校验、金额扣减与追加，并重点展示了异常发生时的回滚机制，确保数据一致性。

本文汇总了利用Python语言对MySQL数据库进行增、删、改、查操作的完整示例，供读者参考学习。

代码片段一

建立数据库连接并执行SQL语句。

#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) #执行

从结果集中提取数据。

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

对数据库执行更新操作。

# 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 银行转账实例

#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("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()

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