小白向大佬迈进的第二天！[自制Json数据库 | 02]
2021/9/24 2:11:38
本文主要是介绍小白向大佬迈进的第二天！[自制Json数据库 | 02]，对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！
上回书说到，这两天突然闲着没事，想自己做一个数据库。
上次是已经把登录系统做完了（见代码）：
import json#json解析
import os#数据读写，文件操作
import sys#控制退出
import time#控制暂停
import shutil#文件夹操作
def saveToJSON(dicObject,file):
flag=False
'''#这一段注释掉了，因为后面发现这样不能完全满足使用需求。
if type(dicObject)!=dict:
print('dict')
return flag
'''
try:
j_file=open("./PyDB/"+file,'a')#打开文件，PyDB是储存数据的文件夹，后面会说到
json.dump(dicObject,j_file,ensure_ascii=False)#以JSON格式储存数据
flag=True
except:
print('写数据出错!')
finally:
if flag:
j_file.close()
return flag
#=========================
def GetFromJSON(filename):
flag=False
dicObject={}
try:
way="./PyDB/"+filename#文件路径
j_file=open(way,'r')#以只读方式打开文件
dicObject=json.load(j_file)#使用json的load方法解析数据
flag=True
except:
flag=False
finally:
if flag:
j_file.close()
elif flag==False:
return False
return dicObject
def turn(file):
with open(file,mode='r',encoding='utf-8') as f:#用with语句打开文件
a=f.readline()#将文件以字符串形式读出
a=a.split('","')#以“，”为间隔，将字符串分割成表格
b=[]#返回的列表
for i in range(len(a)):
if i <= len(a)-2:#a的结尾会有一个‘“，”’，需要把它去掉
b.append(json.loads(a[i]))#用json解析字符串并添加到列表中
return b
if __name__ == '__main__':
print("| Welcome to PyDB Monitor.")#一些简要信息
print("| Server version: 1.0.0 PyDB Server.")
print("| Add '@' at the beginning of the statement.")
print("| Type '@help' or '@h' for help.Type '@continue' or '@c' to clear the current input statement.\n")
print("PyDB>Welcome to PyDB!"+"\n")#欢迎语句
folder=''#判断是否存在数据库文件夹
for i in range(len(os.listdir())):
a=os.listdir()
if a[i]=='PyDB':
folder='PyDB'
if folder!='PyDB':#如果没有，则创建数据库文件夹
os.makedirs('./PyDB'+'./user')
os.makedirs('./PyDB'+'./DataBase')
#----------------------------------------------------登录
while True:
if len(os.listdir('./PyDB/user'))==0:#判断是否存在用户，如果没有，则创建一个超级管理员
print("PyDB> There are no users yet :( ... Let's create one! :) \n")
admin=input("PyDB> Please enter your User Name!\nAdministrator>")
Pass=input("PyDB> Please enter your password!\nPassword>")
RePass=input("PyDB> Please enter your password again!\nPassword>")
if Pass==RePass:#判断两次输入的密码是否一致
#用户信息
info={
'Name':admin,'Password':Pass,'Jurisdiction':'Root'
}
saveToJSON(info,'user/'+admin+'.json')#储存信息
print("\nSuccess>Congratulations, account creation succeeded!\n")
host=GetFromJSON("user/"+admin+".json")#为后面的一些判断做准备
os.makedirs('./PyDB'+'./DataBase'+'./'+admin)#在数据库文件夹下创建用户文件夹
break#跳出循环，进行数据操作
else:#不一致则进入另一个循环
while True:
print('PyDB>The two passwords you entered are different. Please try again.')
Pass=input("PyDB> Please enter your password!\nPassword>")
RePass=input("PyDB> Please enter your password again!\nPassword>")
if Pass==RePass:
info={
'User':admin,'Password':Pass,'Jurisdiction':'Root'
}
saveToJSON(info,'user/'+admin+'.json')
print("\nSuccess>Congratulations, account creation succeeded!\n")
host=GetFromJSON("user/"+admin+".json")
os.makedirs('./PyDB'+'./DataBase'+'./'+admin)
break
break
else:#如果存在用户，则进行登录操作
while True:
admin=input('User name>')
if admin=="@exit":#若需退出，则可以在此退出
print("PyDB>Thank you for your use~ :) Bye!")
time.sleep(3)
sys.exit()
if GetFromJSON("user/"+admin+".json")==False:#判断该用户是否存在
print("Error>Sorry, there is no such user.Please try again.")
else:
host=GetFromJSON("user/"+admin+".json")#获取用户信息
break
Pass=input('Password>')#用户密码
if Pass=="@exit":#若需退出，则可以在此退出
print("PyDB>Thank you for your use~ :) Bye!")
time.sleep(3)
sys.exit()
if host["Password"]!=Pass:#若三次密码错误，则退出程序
print("Error>Password error, please try again!")
Pass=input('Password>')
host=GetFromJSON("user/"+admin+".json")
if host["Password"]!=Pass:
print("Error>Password error, please try again!")
Pass=input('Password>')
host=GetFromJSON("user/"+admin+".json")
if host['Password']!=Pass:
print("Error>You have made three consecutive errors. Please try again later.")
time.sleep(3)
sys.exit()
else:
print("\n"+"PyDB>Welcome,"+admin+'!\n')
break
else:
print("\n"+"PyDB>Welcome,"+admin+'!\n')
break
else:
print("\n"+"PyDB>Welcome,"+admin+'!\n')
break#进入操作界面
那么今天，我们来做后面的数据操作系统！（即第二个大循环）
jurisdiction=host["Jurisdiction"]
maindatabase=''
这个“jurisdiction"就是用户的权限，这个在后面我们会用到（毕竟谁也不想让别人随便创建用户和修改自己的数据）。而”maindataabase"则是使用的数据库，默认为没有选择，需要用户自行选择。
while True:
user_e=input('PyDB>')
User_database_path="PyDB/DataBase/"+admin
这边的user_e就是用户输入的语句，“User_database_path”则是用户的数据库路径。
#----------------------------------------------帮助列表
if user_e=='@h' or user_e=='@help':
DBhelp()
这个帮助函数（DBhelp）是这样子的，要放在循环前，不然会报错：
def DBhelp():
print("Command list:")
print("|Command |Explain |")
print("-----------------------------------------------------------------------")
print("|@choose |Choose a database to use. |")
print("|@create table |Generate a table under the current database. |")
if host["Jurisdiction"]=="Root":
print("|@create user |Create a new user. |")
print("|@c or @continue |Clear the current input statement. |")
print("|@create database |Create a database according to the boot. |")
print("|@del table |Delete a table. |")
print("|@del database |Delete a database. |")
print("|@exit |Exit the program. |")
print("|@h or @help |Get the command list. |")
print("|@insert |Insert data into a table. |")
print("|@show users |View all users. |")
print("|@show tables |View tables under the current database. |")
print("|@show database |View the database under the current user. |")
print("|@query data |Query data in the selected table. |")
print()
就是一个命令列表，因为还在更新，所以不是很全。
主要的命令列表是这样的：
Command（命令） | Explain（解释） |
@choose | Choose a database to use.（选择一个需要使用的数据库） |
@create table | Generate a table under the current database.（在当前数据库下创建一个表格） |
@create user | Create a new user.（创建一个新用户） |
@c or @continue | Clear the current input statement.（清除当前输入的语句） |
@createdatabase | Create a database according to the boot.（根据引导创建数据库） |
@del table | Delete a table.（删除一个表格） |
@del database | Delete a database.（删除一个数据库） |
@exit | Exit the program.（退出程序） |
@h or @help | Get the command list.（获得指令列表） |
@insert | Insert data into a table.（把数据插入到表格中） |
@show users | View all users.（查看所有的用户） |
@show tables | View tables under the current database.（查看当前数据库下的所有表格） |
@show database | iew the database under the current user.（查看当前用户下的所有数据库） |
@query data | Query data in the selected table. |
以上是这个数据库的指令列表（还在更新），所有的操作只需要根据引导去做即可。
所有指令对应的操作都在后面（不是按表格顺序来）：
清除当前输入的语句：
if user_e=='@c' or user_e=='@continue':
continue
很简单，直接跳过就好了。
退出程序：
elif user_e=='@exit':
print("PyDB>Thank you for your use~ :) Bye!")
time.sleep(3)
sys.exit()
打印一个告别语，等待三秒，退出~~
选择数据库：
elif user_e=='@choose':
maindatabase=input('Select>')
find=os.listdir(User_database_path)
yesorno=False
for i in find:
if i==maindatabase:
yesorno=True
if yesorno==False:
print("Error>This database does not exist.\n")
else:
print('PyDB>Database changed.\n')
先获取输入的数据库，然后用os的lisetdir方法在当前用户文件夹下循环查找，如不存在则报错，若存在则说明“数据库改变了”，同时改变“maindatabae”。
展示数据库：
elif user_e=="@show database":
database_num=os.listdir(User_database_path)
databases=''
if database_num==[]:
print("PyDB>There is no database yet. Use '@create database' to create one!\n")
else:
for i in range(len(database_num)):
if i<len(database_num)-1:
databases+=database_num[i]+','
else:
databases+=database_num[i]
print(" | "+databases+' |')
用os库的listdir方法获取用户目录下的文件夹（数据库）并打印，若没有则提示创建一个。
创建数据库：
elif user_e=="@create database":
database_num=os.listdir(User_database_path)
basename=input("PyDB>Please enter the Name of the Database.\nCreate>")
os.makedirs('./PyDB'+'./DataBase'+'./'+admin+'./'+basename)
print("Success>Database creation succeeded!\n")
同样用os的lisetdir方法判断该数据库是否存在，如不存在则创建并打印提示信息。
创建表格：
elif user_e=="@create table":
if maindatabase=='':
print("PyDB>Please choose a database first!\n")
else:
tablename=input('PyDB>Please enter the name of the table.\nCreate>')
database_path=os.listdir('PyDB/Database/'+admin+'/'+maindatabase)
yesorno=False
for i in database_path:
i=i.replace(".json",'')
if i==tablename:
yesorno=True
if yesorno==True:
print("Error>This table already exists.\n")
else:
columns=input("PyDB>Please enter the title of each column.\nCreate>")
columns=columns.split(',')
column_dict={}
for i in range(len(columns)):
column_dict.setdefault(str(i+1),columns[i])
saveToJSON(column_dict,'Database/'+admin+'/'+maindatabase+'/'+tablename+'.json')
saveToJSON(',','Database/'+admin+'/'+maindatabase+'/'+tablename+'.json')
print("Success>Successfully created the table!\n")
敲黑板了啊！这个是重点之一！首先，查看有没有选择数据库，然后就是老方法，用listdir判断是否存在这个表格。但是因为表格是用json文件格式储存的，所以在判断时必须在表格名称后面加上“.json”后缀或者将获取到的文件名称去掉后缀".json"，不然就无法正确的判断出是否存在这个表格。
展示表格：
elif user_e=="@show tables":
if maindatabase=='':
print("PyDB>Please choose a database first!\n")
else:
database_path=os.listdir('PyDB/Database/'+admin+'/'+maindatabase)
if database_path==[]:
print("PyDB>There is no table yet. Use '@create table' to create one!\n")
else:
show_tables=''
for i in range(len(database_path)):
toshow=database_path[i]
if i<len(database_path)-1:
show_tables+=toshow.replace('.json','')+','
else:
show_tables+=toshow.replace('.json','')
print(' |'+show_tables+' |\n')
首先，查看有没有选择数据库，其他的和上面的展示数据库差不多，这里就不过多赘述了。
删除数据库：
elif user_e=="@del database":
del_base=input("PyDB>Please enter the name of the database to delete.\nDelete>")
database_path=os.listdir('PyDB/Database/'+admin)
yesorno=False
for i in database_path:
if i==del_base:
yesorno=True
if yesorno==False:
print("Error>This database doesn't exists.\n")
else:
database_path=os.listdir('PyDB/Database/'+admin+'/'+del_base)
if database_path==[]:
if maindatabase==del_base:
maindatabase=''
os.rmdir('PyDB/Database/'+admin+'/'+del_base)
print("Success> Successfully deleted this database!\n")
else:
while True:
sure=input("\nPyDB>Are you sure to delete?This database is not empty!(Y/N)\nDelete>")
if sure=='Y' or sure=='y':
shutil.rmtree('PyDB/Database/'+admin+'/'+del_base)
print('Success> Successfully deleted this database!')
if maindatabase==del_base:
maindatabase=''
break
elif sure=='N' or sure=='n':
print('PyDB> Cancel deletion.\n')
break
还是老方法，先用listdir判断这个数据库是否存在，如若存在，在判断这是不是个空数据库。如果是，那就是直接删掉；如果不是，则会提示这个数据库不为空，是否确定删除？确定了，那就用shutil的mrtree方法，循环删除数据库内的内容。
今天的最后一个功能，也是数据库最核心的功能：插入数据
elif user_e=="@insert":
if maindatabase=='':
print("PyDB>Please choose a database first!")
else:
insert_table=input("PyDB>Please choose a table.\nInsert>")
find=os.listdir(User_database_path+'/'+maindatabase)
yesorno=False
for i in find:
if i==insert_table+'.json':
yesorno=True
if yesorno==False:
print("Error>Sorry, this form does not exist.\n")
else:
toshow=turn(User_database_path+'/'+maindatabase+'/'+insert_table+'.json')[0]
toshow=str(toshow).replace('{','')
toshow=toshow.replace('}','')
toshow=toshow.replace("'",'')
print("PyDB>The titles of the columns are |"+toshow+'|.')
toinsert=input("PyDB>Please enter the data to insert!\nInsert>")
toinsert=toinsert.split(',')
toshow=turn(User_database_path+'/'+maindatabase+'/'+insert_table+'.json')[0]
listshow=list(toshow)
tosave={}
if len(toinsert)==len(listshow):
for i in range(len(list(toshow))):
head=toshow[listshow[i]]
tosave.setdefault(head,toinsert[i])
waytos=input("PyDB>Please choose the way to insert!\nInsert>")
if waytos=='end':
try:
saveToJSON(tosave,'DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
print("Success>Successfully inserted data!\n")
except:
print("Error>There is some thing wrong with saving it!\n")
elif waytos=='top':
try:
lastin=turn(User_database_path+'/'+maindatabase+'/'+insert_table+'.json')
with open(User_database_path+'/'+maindatabase+'/'+insert_table+'.json',mode='w',encoding='utf-8') as f:
json.dump(lastin[0],f)
lastin.pop(0)
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(tosave,'DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
for i in range(len(lastin)):
saveToJSON(lastin[i],'DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
print("Success>Successfully inserted data!\n")
except:
print("Error>There is some thing wrong with saving it!\n")
elif len(turn(User_database_path+'/'+maindatabase+'/'+insert_table+'.json'))==int(waytos):
try:
saveToJSON(tosave,'DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
print("Success>Successfully inserted data!\n")
except:
print("Error>There is some thing wrong with saving it!\n")
elif int(waytos)==1:
try:
lastin=turn(User_database_path+'/'+maindatabase+'/'+insert_table+'.json')
with open(User_database_path+'/'+maindatabase+'/'+insert_table+'.json',mode='w',encoding='utf-8') as f:
json.dump(lastin[0],f)
lastin.pop(0)
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(tosave,'DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
for i in range(len(lastin)):
saveToJSON(lastin[i],'DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
print("Success>Successfully inserted data!\n")
except:
print("Error>There is some thing wrong with saving it!\n")
elif 1<int(waytos)<len(turn(User_database_path+'/'+maindatabase+'/'+insert_table+'.json')):
inwaytos=int(waytos)
try:
lastin=turn(User_database_path+'/'+maindatabase+'/'+insert_table+'.json')
with open(User_database_path+'/'+maindatabase+'/'+insert_table+'.json',mode='w',encoding='utf-8') as f:
json.dump(lastin[0],f)
for i in range(inwaytos):
lastin.pop(i)
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(tosave,'DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
for i in range(len(lastin)):
saveToJSON(lastin[i],'DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
print("Success>Successfully inserted data!\n")
except:
print("Error>There is some thing wrong with saving it!\n")
else:
print('Error>The information entered is incorrect!\n')
插入数据呢分为三种方式……详细呢，我们下节再介绍，嘿嘿嘿~~
（其实python代码的可读性还是很高的，主要还是靠自己阅读代码，就和语文的阅读理解一样，多读才能提高水平~~好吧，说白了就是我懒QwQ）
今日代码小结：
import json
import os
import sys
import time
import shutil
#-----------------------
def turn(file):
with open(file,mode='r',encoding='utf-8') as f:
a=f.readline()
a=a.split('","')
b=[]
for i in range(len(a)):
if i <= len(a)-2:
b.append(json.loads(a[i]))
return b
def saveToJSON(dicObject,file):
flag=False
'''if type(dicObject)!=dict:
print('dict')
return flag'''
try:
j_file=open("./PyDB/"+file,'a')
json.dump(dicObject,j_file,ensure_ascii=False)
flag=True
except:
print('写数据出错!')
finally:
if flag:
j_file.close()
return flag
#=========================
def GetFromJSON(filename):
flag=False
dicObject={}
try:
way="./PyDB/"+filename
j_file=open(way,'r')
dicObject=json.load(j_file)
flag=True
except:
flag=False
finally:
if flag:
j_file.close()
elif flag==False:
return False
return dicObject
#----------------------------------------
def DBhelp():
print("Command list:")
print("|Command |Explain |")
print("-----------------------------------------------------------------------")
print("|@choose |Choose a database to use. |")
print("|@create table |Generate a table under the current database. |")
if host["Jurisdiction"]=="Root" or host["Jurisdiction"]=="Hang Jiayu":
print("|@create user |Create a new user. |")
print("|@c or @continue |Clear the current input statement. |")
print("|@create database |Create a database according to the boot. |")
print("|@del table |Delete a table. |")
print("|@del database |Delete a database. |")
print("|@exit |Exit the program. |")
print("|@h or @help |Get the command list. |")
print("|@insert |Insert data into a table. |")
print("|@show users |View all users. |")
print("|@show tables |View tables under the current database. |")
print("|@show database |View the database under the current user. |")
print("|@query data |Query data in the selected table. |")
print()
#----------------------------------------
if __name__ == '__main__':
print("| Welcome to PyDB Monitor.")
print("| Server version: 1.0.0 PyDB Server.")
print("| Add '@' at the beginning of the statement.")
print("| Type '@help' or '@h' for help.Type '@continue' or '@c' to clear the current input statement.\n")
print("PyDB>Welcome to PyDB!"+"\n")
folder=''
for i in range(len(os.listdir())):
a=os.listdir()
if a[i]=='PyDB':
folder='PyDB'
if folder!='PyDB':
os.makedirs('./PyDB'+'./user')
os.makedirs('./PyDB'+'./DataBase')
#----------------------------------------------------Sing in
while True:
if len(os.listdir('./PyDB/user'))==0:
print("PyDB> There are no users yet :( ... Let's create one! :) \n")
admin=input("PyDB> Please enter your User Name!\nAdministrator>")
Pass=input("PyDB> Please enter your password!\nPassword>")
RePass=input("PyDB> Please enter your password again!\nPassword>")
if Pass==RePass:
info={
'Name':admin,'Password':Pass,'Jurisdiction':'Root'
}
saveToJSON(info,'user/'+admin+'.json')
print("\nSuccess>Congratulations, account creation succeeded!\n")
host=GetFromJSON("user/"+admin+".json")
os.makedirs('./PyDB'+'./DataBase'+'./'+admin)
break
else:
while True:
print('PyDB>The two passwords you entered are different. Please try again.')
Pass=input("PyDB> Please enter your password!\nPassword>")
RePass=input("PyDB> Please enter your password again!\nPassword>")
if Pass==RePass:
info={
'User':admin,'Password':Pass,'Jurisdiction':'Root'
}
saveToJSON(info,'user/'+admin+'.json')
print("\nSuccess>Congratulations, account creation succeeded!\n")
host=GetFromJSON("user/"+admin+".json")
os.makedirs('./PyDB'+'./DataBase'+'./'+admin)
break
break
else:
while True:
admin=input('User name>')
if admin=="@exit":
print("PyDB>Thank you for your use~ :) Bye!")
time.sleep(3)
sys.exit()
if GetFromJSON("user/"+admin+".json")==False:
print("Error>Sorry, there is no such user.Please try again.")
else:
host=GetFromJSON("user/"+admin+".json")
break
Pass=input('Password>')
if Pass=="@exit":
print("PyDB>Thank you for your use~ :) Bye!")
time.sleep(3)
sys.exit()
if host["Password"]!=Pass:
print("Error>Password error, please try again!")
Pass=input('Password>')
host=GetFromJSON("user/"+admin+".json")
if host["Password"]!=Pass:
print("Error>Password error, please try again!")
Pass=input('Password>')
host=GetFromJSON("user/"+admin+".json")
if host['Password']!=Pass:
print("Error>You have made three consecutive errors. Please try again later.")
time.sleep(3)
sys.exit()
else:
print("\n"+"PyDB>Welcome,"+admin+'!\n')
break
else:
print("\n"+"PyDB>Welcome,"+admin+'!\n')
break
else:
print("\n"+"PyDB>Welcome,"+admin+'!\n')
break
jurisdiction=host["Jurisdiction"]
maindatabase=''
#-----------------------------------------------------------Console
while True:
user_e=input('PyDB>')
User_database_path="PyDB/DataBase/"+admin
#----------------------------------------------Help
if user_e=='@h' or user_e=='@help':
DBhelp()
#----------------------------------------------continue
if user_e=='@c' or user_e=='@continue':
continue
#----------------------------------------------Exit
elif user_e=='@exit':
print("PyDB>Thank you for your use~ :) Bye!")
time.sleep(3)
sys.exit()
#----------------------------------------------Choose Database
elif user_e=='@choose':
maindatabase=input('Select>')
find=os.listdir(User_database_path)
yesorno=False
for i in find:
if i==maindatabase:
yesorno=True
if yesorno==False:
print("Error>This database does not exist.\n")
else:
print('PyDB>Database changed.\n')
#----------------------------------------------Show Database
elif user_e=="@show database":
database_num=os.listdir(User_database_path)
databases=''
if database_num==[]:
print("PyDB>There is no database yet. Use '@create database' to create one!\n")
else:
for i in range(len(database_num)):
if i<len(database_num)-1:
databases+=database_num[i]+','
else:
databases+=database_num[i]
print(" | "+databases+' |')
#----------------------------------------------Create Database
elif user_e=="@create database":
database_num=os.listdir(User_database_path)
basename=input("PyDB>Please enter the Name of the Database.\nCreate>")
os.makedirs('./PyDB'+'./DataBase'+'./'+admin+'./'+basename)
print("Success>Database creation succeeded!\n")
#----------------------------------------------Create Table
elif user_e=="@create table":
if maindatabase=='':
print("PyDB>Please choose a database first!\n")
else:
tablename=input('PyDB>Please enter the name of the table.\nCreate>')
database_path=os.listdir('PyDB/Database/'+admin+'/'+maindatabase)
yesorno=False
for i in database_path:
i=i.replace(".json",'')
if i==tablename:
yesorno=True
if yesorno==True:
print("Error>This table already exists.\n")
else:
columns=input("PyDB>Please enter the title of each column.\nCreate>")
columns=columns.split(',')
column_dict={}
for i in range(len(columns)):
column_dict.setdefault(str(i+1),columns[i])
print("Success>Successfully created the table!\n")
saveToJSON(column_dict,'Database/'+admin+'/'+maindatabase+'/'+tablename+'.json')
saveToJSON(',','Database/'+admin+'/'+maindatabase+'/'+tablename+'.json')
#----------------------------------------------show tables
elif user_e=="@show tables":
if maindatabase=='':
print("PyDB>Please choose a database first!\n")
else:
database_path=os.listdir('PyDB/Database/'+admin+'/'+maindatabase)
if database_path==[]:
print("PyDB>There is no table yet. Use '@create table' to create one!\n")
else:
show_tables=''
for i in range(len(database_path)):
toshow=database_path[i]
if i<len(database_path)-1:
show_tables+=toshow.replace('.json','')+','
else:
show_tables+=toshow.replace('.json','')
print(' |'+show_tables+' |\n')
#----------------------------------------------delete database
elif user_e=="@del database":
del_base=input("PyDB>Please enter the name of the database to delete.\nDelete>")
database_path=os.listdir('PyDB/Database/'+admin)
yesorno=False
for i in database_path:
if i==del_base:
yesorno=True
if yesorno==False:
print("Error>This database doesn't exists.\n")
else:
database_path=os.listdir('PyDB/Database/'+admin+'/'+del_base)
if database_path==[]:
if maindatabase==del_base:
maindatabase=''
os.rmdir('PyDB/Database/'+admin+'/'+del_base)
print("Success> Successfully deleted this database!\n")
else:
while True:
sure=input("\nPyDB>Are you sure to delete?This database is not empty!(Y/N)\nDelete>")
if sure=='Y' or sure=='y':
shutil.rmtree('PyDB/Database/'+admin+'/'+del_base)
print('Success> Successfully deleted this database!')
if maindatabase==del_base:
maindatabase=''
break
elif sure=='N' or sure=='n':
print('PyDB> Cancel deletion.\n')
break
#----------------------------------------------insert data
elif user_e=="@insert":
if maindatabase=='':
print("PyDB>Please choose a database first!")
else:
insert_table=input("PyDB>Please choose a table.\nInsert>")
find=os.listdir(User_database_path+'/'+maindatabase)
yesorno=False
for i in find:
if i==insert_table+'.json':
yesorno=True
if yesorno==False:
print("Error>Sorry, this form does not exist.\n")
else:
toshow=turn(User_database_path+'/'+maindatabase+'/'+insert_table+'.json')[0]
toshow=str(toshow).replace('{','')
toshow=toshow.replace('}','')
toshow=toshow.replace("'",'')
print("PyDB>The titles of the columns are |"+toshow+'|.')
toinsert=input("PyDB>Please enter the data to insert!\nInsert>")
toinsert=toinsert.split(',')
toshow=turn(User_database_path+'/'+maindatabase+'/'+insert_table+'.json')[0]
listshow=list(toshow)
tosave={}
if len(toinsert)==len(listshow):
for i in range(len(list(toshow))):
head=toshow[listshow[i]]
tosave.setdefault(head,toinsert[i])
waytos=input("PyDB>Please choose the way to insert!\nInsert>")
if waytos=='end':
try:
saveToJSON(tosave,'DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
print("Success>Successfully inserted data!\n")
except:
print("Error>There is some thing wrong with saving it!\n")
elif waytos=='top':
try:
lastin=turn(User_database_path+'/'+maindatabase+'/'+insert_table+'.json')
with open(User_database_path+'/'+maindatabase+'/'+insert_table+'.json',mode='w',encoding='utf-8') as f:
json.dump(lastin[0],f)
lastin.pop(0)
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(tosave,'DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
for i in range(len(lastin)):
saveToJSON(lastin[i],'DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
print("Success>Successfully inserted data!\n")
except:
print("Error>There is some thing wrong with saving it!\n")
elif len(turn(User_database_path+'/'+maindatabase+'/'+insert_table+'.json'))==int(waytos):
try:
saveToJSON(tosave,'DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
print("Success>Successfully inserted data!\n")
except:
print("Error>There is some thing wrong with saving it!\n")
elif int(waytos)==1:
try:
lastin=turn(User_database_path+'/'+maindatabase+'/'+insert_table+'.json')
with open(User_database_path+'/'+maindatabase+'/'+insert_table+'.json',mode='w',encoding='utf-8') as f:
json.dump(lastin[0],f)
lastin.pop(0)
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(tosave,'DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
for i in range(len(lastin)):
saveToJSON(lastin[i],'DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
print("Success>Successfully inserted data!\n")
except:
print("Error>There is some thing wrong with saving it!\n")
elif 1<int(waytos)<len(turn(User_database_path+'/'+maindatabase+'/'+insert_table+'.json')):
inwaytos=int(waytos)
try:
lastin=turn(User_database_path+'/'+maindatabase+'/'+insert_table+'.json')
with open(User_database_path+'/'+maindatabase+'/'+insert_table+'.json',mode='w',encoding='utf-8') as f:
json.dump(lastin[0],f)
for i in range(inwaytos):
lastin.pop(i)
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(tosave,'DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
for i in range(len(lastin)):
saveToJSON(lastin[i],'DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
saveToJSON(',','DataBase/'+admin+'/'+maindatabase+'/'+insert_table+'.json')
print("Success>Successfully inserted data!\n")
except:
print("Error>There is some thing wrong with saving it!\n")
else:
print('Error>The information entered is incorrect!\n')
那么今天的介绍就到这里了，如果大家有建议或更好的方法，欢迎在评论区留言哦！我们下期再见，Bye~~
（PS：其中一段代码有个小细节哦~找到的人在评论区打出来吧~）
这篇关于小白向大佬迈进的第二天！[自制Json数据库 | 02]的文章就介绍到这儿，希望我们推荐的文章对大家有所帮助，也希望大家多多支持为之网！
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