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Python连接MySQL数据库方法介绍( 四 )

Pythonmysql


print("输入有误，请重新输入！")
def Start():
print("********************************************************")
print("* 欢迎来到FIFA球员信息系统 *")
print("*1.查看球员信息 2.球员信息录入 *")
print("*3.球员能力 4.删除球员信息 *")
print("*5.退出系统 *")
print("********************************************************")
choice = input("请输入您的选择：")
Search_choice(choice)
if __name__=="__main__":
Start()
银行转账系统
先建立数据库test_3和表bankdata
import pymysql
config = {
'host': '127.0.0.1',
'port': 3306,
'user': 'root',
'passwd': 'password',
'charset':'utf8',
}
conn = pymysql.connect(**config)
cursor = conn.cursor()
try:
# 创建数据库
DB_NAME = 'test_3'
cursor.execute('DROP DATABASE IF EXISTS %s' %DB_NAME)
cursor.execute('CREATE DATABASE IF NOT EXISTS %s' %DB_NAME)
conn.select_db(DB_NAME)
#创建表
TABLE_NAME = 'bankData'
cursor.execute('CREATE TABLE %s(id int primary key,money int(30))' %TABLE_NAME)
# 批量插入纪录
values = []
for i in range(20):
values.append((int(i),int(156*i)))
cursor.executemany('INSERT INTO bankData values(%s,%s)',values)
conn.commit()
# 查询数据条目
count = cursor.execute('SELECT * FROM %s' %TABLE_NAME)
print ('total records:{}'.format(cursor.rowcount))
# 获取表名信息
desc = cursor.description
print ("%s %3s" % (desc[0][0], desc[1][0]))
cursor.scroll(10,mode='absolute')
results = cursor.fetchall()
for result in results:
print (result)
except:
import traceback
traceback.print_exc()
# 发生错误时会滚
conn.rollback()
finally:
# 关闭游标连接
cursor.close()
# 关闭数据库连接
conn.close()
构建系统
import pymysql
class TransferMoney(object):
# 构造方法
def __init__(self, conn):
self.conn = conn
self.cur = conn.cursor()
def transfer(self, source_id, target_id, money):
if not self.check_account_avaialbe(source_id):
raise Exception("账户不存在")
if not self.check_account_avaialbe(target_id):
raise Exception("账户不存在")
if self.has_enough_money(source_id, money):
try:
self.reduce_money(source_id, money)
self.add_money(target_id, money)
except Exception as e:
print("转账失败:", e)
self.conn.rollback()
else:
self.conn.commit()
print("%s给%s转账%s金额成功" % (source_id, target_id, money))
def check_account_avaialbe(self, acc_id):
"""判断帐号是否存在，传递的参数是银行卡号的id"""
select_sqli = "select * from bankData where id=%d;" % (acc_id)
print("execute sql:", select_sqli)
res_count = self.cur.execute(select_sqli)
if res_count == 1:
return True
else:
# raise Exception("账户%s不存在" %(acc_id))
return False
def has_enough_money(self, acc_id, money):
"""判断acc_id账户上金额> money"""
# 查找acc_id存储金额?
select_sqli = "select money from bankData where id=%d;" % (acc_id)
print("execute sql:", select_sqli)
self.cur.execute(select_sqli) # ((1, 500), )
# 获取查询到的金额钱数;
acc_money = self.cur.fetchone()[0]
# 判断
if acc_money >= money:
return True
else:
return False
def add_money(self, acc_id, money):
update_sqli = "update bankData set money=money+%d where id=%d" % (money, acc_id)
print("add money:", update_sqli)
self.cur.execute(update_sqli)
def reduce_money(self, acc_id, money):
update_sqli = "update bankData set money=money-%d where id=%d" % (money, acc_id)
print("reduce money:", update_sqli)
self.cur.execute(update_sqli)
# 析构方法
def __del__(self):
self.cur.close()
self.conn.close()
if __name__ == '__main__':
# 1. 连接数据库，
conn = pymysql.connect(host = '127.0.0.1' # 连接名称，默认127.0.0.1
,user = 'root' # 用户名
,passwd='password' # 密码
,port= 3306 # 端口，默认为3306
,db='test_3' # 数据库名称
,charset='utf8'
,autocommit=True, # 如果插入数据，自动提交给数据库


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