模拟MySQL命令

staff_table

1,Alex Li,22,13651054608,IT,2013-04-01
2,Jack Wang,30,13304320533,HR,2015-05-03
3,Rain Liu,25,1383235322,Saies,2016-04-22
4,Mmck Cao,40,1356145343,HR,2009-03-01

+---------------------------------------READ ME-------------------------------------------------+
|   注：命令及关键字请使用小写
|       本代码为模拟简单的 MySQL 增删改查的功能，可参考给的例子，自行输入
+-----------------------------------------------------------------------------------------------+
|   * 的位置表示显示范围，也可以输入表头名字，只打印这几列
|  范围 的位置，表示查找（修改）的条件，可以用and连接多个参数
|   (field1,field2) 表示你增加时需要写入的列的名字， phone 必选
|   values(value1,value2) 表示你增加时需要写入的列的数值
+-----------------------------------------------------------------------------------------------+
|   查找：select * from staff_table where 范围
|        :select * from staff_table where age > 22 and dept = "HR" and enroll_date like ""
|        :select name,age from staff_table where age > 22
+-----------------------------------------------------------------------------------------------+
|   插入：insert into staff_table (field1,field2) values(value1,value2)
|        :insert into staff_table (name,age,phone,dept) values ('jia',22,15246512541,'IT')
+-----------------------------------------------------------------------------------------------+
|   删除：delete from staff_table where 范围
|        :delete from staff_table where staff_id = 3
+-----------------------------------------------------------------------------------------------+
|   更新：update staff_table set field1=value1 where 范围
|        :update staff_table set age = 23 where staff_id = 1
+-----------------------------------------------------------------------------------------------+
  退出：q    再看一遍说明：r

low_B的代码

 #! /usr/bin/env python
 # -*- coding: utf-8 -*-
 # __author__ = "Always"
 # Date: 2017/6/16
 import time

 file_path = r'staff_table'
 readme_path = r'readme.txt'
 all_tittle = ['staff_id', 'name', 'age','phone', 'dept', 'enroll_date']
 func_dic = {}

 def add_func_dic(keys):
     def deco(func):
         func_dic[keys] = func
     return deco

 def resolve_cmd(cmd):
     """
     分解命令
     这个函数，主要是用来处理接收的 select 命令，将各个参数提取出来，放到一个字典中
     :param cmd:  这个参数是用户输入的，命令，格式为字符串形式
     :return:
     """
     cmd_dict = {'show_tittle':None, 'file_name':None, 'select_condetion':None, 'cmd':None}
     cmd_deal = cmd.split('from')[0].split()
     cmd_dict['cmd'] = cmd_deal.pop(0).strip()
     cmd_deal = ''.join(cmd_deal).split(',')
     cmd_dict['show_tittle'] = all_tittle if cmd_deal[0].strip() == "*" else cmd_deal
     filename_select = cmd.split('from')[1].strip().split('where')
     cmd_dict['file_name'] = filename_select[0].strip()
     if len(filename_select) > 1:
         cmd_dict['select_condetion'] = filename_select[1].strip()
     return cmd_dict

 def deal_select_condetion(select_condetion):
     """
     主要用来处理后面的条件有 like 的情况，为筛选的条件重新排序
     :param select_condetion:
     :return:
     """
     select_condetion = select_condetion.split('and')
     for i in range(len(select_condetion)):
         if 'like' in select_condetion[i]:
             select_condetion[i] = select_condetion[i].split()
             select_condetion[i].reverse()
             select_condetion[i] = ' '.join(select_condetion[i])
     return ' and '.join(select_condetion).replace('like', 'in')

 def return_select_result(total_count, all_tittle, show_tittle, d):
     """
     这个函数主要用来处理打印满足条件的行数和列数
     :param total_count: 用来计算一共打印了多少行
     :param all_tittle: 所有的表头，用来固定打印顺序
     :param show_tittle: 代表需要打印的列
     :return: 用来计算一共打印了多少行
     """
     for tittle in all_tittle:
         if tittle in show_tittle:
             print('%-14s' % d[tittle], end='')
     print()
     total_count += 1
     return total_count

 @add_func_dic('select')
 def what_a_funck(cmd):
     cmd_dict = resolve_cmd(cmd)
     select(cmd_dict['file_name'], cmd_dict['select_condetion'], cmd_dict['show_tittle'])

 def select(file_name, select_condetion, show_tittle):
     """
     这个功能用来查找，并打印符合要求的字段
     :param file_name
     :param select_condetion
     :param show_tittle
     :return:
     """
     file_info_list = get_file_info_to_list(file_name)

     for tittle in all_tittle:                         # 打印表头
         if tittle in show_tittle:
             print('\033[44;1m%-14s' % tittle, end='')
     print('\033[0m')
     total_count = 0

     if select_condetion:                   # 如果有筛选条件的话，按条件打印，没有的话，全部打印
         select_condetion = select_condetion.replace('=', '==')  # 如果判断条件有一个 ’=‘ 就把他变成两个，方便后面 eval 计算
         if 'like' in select_condetion:  # 如果判断条件有 like 就把   enroll_date like "2013"  改成 “2013” in enroll_date ，方便后面 eval 计算
             select_condetion = deal_select_condetion(select_condetion)

         for d in file_info_list:                          # 遍历 用户信息 列表
             globals().update(d)                           # 将字典中所有内容变为变量，用来处理条件
             show_table_tittle = False
             if eval(select_condetion):                    # 如果满足输入的条件，那么打印信息

                 total_count = return_select_result(total_count,all_tittle,show_tittle, d)
     else:                                                 # 如果用户没有输入筛选条件，执行这里
         for d in file_info_list:
             total_count = return_select_result(total_count, all_tittle, show_tittle, d)
     print('\033[1mtotal count: %s\033[0m'%total_count)

 def get_file_info_to_list(file_path):               # 将文件内容取出来，放入 [{},{}] 中
     with open (file_path,encoding='utf-8') as f:
         return [{'staff_id':int(line.strip().split(',')[0]), 'name':line.strip().split(',')[1], 'age':int(line.strip().split(',')[2]), 'phone':line.strip().split(',')[3], 'dept':line.strip().split(',')[4], 'enroll_date':line.strip().split(',')[5]} for line in f]

 def insert_split(cmd):                                 # 插入功能的前戏
     """
     插入功能的命令分解。。。
     :param cmd: 用户输入的命令
     :return: 包含分解的命令的字典
     """
     cmd_dict = {}
     cmd_split = cmd.split()
     if cmd_split[1] != 'into':
         return
     cmd_dict['file_name'] = cmd_split[2]
     cmd_split = ''.join(cmd_split[3:]).split('values')
     cmd_dict['keys'] = cmd_split[0].strip('(').strip(')').split(',')
     cmd_dict['values'] = cmd_split[1].strip('(').strip(')').split(',')
     return cmd_dict

 @add_func_dic('insert')
 def insert(cmd, all_tittle = all_tittle, file_path = file_path):               # 插入功能的开始
     """
     插入功能，新增一个用户
     :param cmd: 传入命令行的输入，进行分解调用
     :param all_tittle: 默认为全局变量，用来判断需要写入那些内容，以及位置排序
     :param file_path: 默认为全局变量，用来标记需要修改的文件名
     :return:
     """
     if not insert_split(cmd):
         print('输入错误。。。')
         return
     cmd_dict = insert_split(cmd)
     globals().update(cmd_dict)
     file_info_list = get_file_info_to_list(file_path)
     new_people_info = {'staff_id':file_info_list[-1]['staff_id'] + 1}
     if 'phone' not in keys:
         print('哥，我也不想的，老师指定 phone 为唯一键，不输入不行啊。。。。')
         return

     for i in file_info_list:                                            # 如果号码重复，重新输入
         if i['phone'] == values[keys.index('phone')]:
             print('那啥，号码已注册，换一个吧。。亲。。。。')
             return
     if 'age' in keys and not values[keys.index('age')].isdigit():               # 判断年龄是不是数字
         print('年龄需要为数字。。。')
         return

     for i in all_tittle[1:]:                  # 准备加入 新人物 的信息
         if i in keys:
             new_people_info[i] = values[keys.index(i)].strip("'").strip('"')
         else:
             new_people_info[i] = None
     new_people_info = [new_people_info]
     add_new_people(all_tittle, new_people_info, file_path, open_with='a')
     print('\033[1m加入成功。。。\033[0m')

 def add_new_people(all_tittle,new_people_info, file_path, open_with = 'r'):
     """
     主要用来写入或增加 staff_table 的内容
     :param all_tittle: 存放表头信息
     :param new_people_info: 需要加入，或重新写入的任务信息
     :param file_path: 文件路径
     :param open_with: 打开方式
     :return: 1
     """
     with open(file_path, open_with, encoding='utf-8') as f:
         new_people_info_str = ''
         if new_people_info[0]['enroll_date'] == None:
             new_people_info[0]['enroll_date'] = time.strftime("%Y-%m-%d")

         for d in new_people_info:
             for i in all_tittle:
                 new_people_info_str += '%s,'%d[i]
             new_people_info_str = new_people_info_str.strip(',') + '\n'
         f.write(new_people_info_str)
         return 1

 @add_func_dic('delete')
 def delete(cmd1):
     """
     处理删除命令，通过匹配符合条件的方法，不符合的加入新的列表中，等待重新写入
     :param cmd1: 用户输入的命令
     :return: 1
     """
     cmd_dic = resolve_cmd(cmd1)
     cmd, file_name, select_condetion = cmd_dic['cmd'], cmd_dic['file_name'], cmd_dic['select_condetion']

     if select_condetion:
         select_condetion = select_condetion.replace('=', '==')
         if 'like' in select_condetion:               # 如果判断条件有 like 就把   enroll_date like "2013"  改成 “2013” in enroll_date ，方便后面 eval 计算
             select_condetion = deal_select_condetion(select_condetion)
     else:
         print("请输入条件。。。。")
         return

     file_info_list = get_file_info_to_list(file_name)   # 获取文件相关参数
     new_file_list = []            # 筛选出新信息后重新写入
     total_count = 0
     for d in file_info_list:
         globals().update(d)
         if not eval(select_condetion):
             new_file_list.append(d)
         else:
             total_count += 1
     add_new_people(all_tittle,new_file_list,file_name,open_with='w')
     print('\033[1m删除了%s条内容。。。\033[0m' % total_count)
     return 1

 def update_split(cmd):
     """
     处理用户更新信息时候的命令，将它分割开
     :param cmd: 用户输入的信息
     :return: 分割好的内容 file_name, change_thing, select_condetion
     """
     cmd_dic={}
     cmd_dic['file_name'] = cmd.split('set')[0].split('update')[1].strip()
     cmd_dic['change_thing'] = cmd.split('where')[0].split('set')[1].strip().split('=')
     if 'staff_id' in cmd_dic['change_thing'][1]:
         print('哥，为了方便程序运行，我禁止了修改 ID 。。。。')
         return
     if 'where' not in cmd:
         print('没有输入范围(where)。。。')
         return
     cmd_dic['select_condetion'] = cmd.split('where')[1].strip()
     if 'age' in cmd_dic['change_thing']:
         if not cmd_dic['change_thing'][1].isdigit():
             print('年龄要是个数字。。。。')
             return
     return cmd_dic['file_name'], cmd_dic['change_thing'], cmd_dic['select_condetion']

 @add_func_dic('update')
 def update(cmd):
     """
     这个程序用来修改数据库信息
     :param cmd: 用户输入的命令
     :return: 1
     """
     cmd_dic = update_split(cmd)
     if not cmd_dic:
         return
     file_name, change_thing, select_condetion = update_split(cmd)
     select_condetion = select_condetion.replace('=','==')
     if 'like' in select_condetion:  # 如果判断条件有 like 就把   enroll_date like "2013"  改成 “2013” in enroll_date ，方便后面 eval 计算
         select_condetion = deal_select_condetion(select_condetion)
     file_info_list = get_file_info_to_list(file_name)
     total_count = 0
     for i,d in enumerate(file_info_list):
         globals().update(d)
         if eval(select_condetion):
             file_info_list[i][change_thing[0].strip()] = change_thing[1].strip()
             total_count += 1

     add_new_people(all_tittle,file_info_list, file_name, open_with = 'w')
     print('\033[1m修改了%s条内容。。。\033[0m' % total_count)

 def main():
     while True:
         with open(readme_path,encoding='utf-8') as f:
             for i in f:
                 print(i.strip())
         while True:
             cmd = input("\033[31;1m>>>\033[0m").strip()
             if cmd.upper() == 'Q':
                 exit('谢谢使用')
             elif cmd.upper() == 'R':
                 break
             try:
                 func_dic[cmd.strip().split()[0]](cmd)
             except Exception:
                 print('输入错误。。。')
             time.sleep(0.3)

 if __name__ == "__main__":
     main()

仿MySQL