Python使用shelve模块实现简单数据存储的方法

#!/usr/bin/python
import sys, shelve
def store_person(db):
 """
 Query user for data and store it in the shelf object
 """
 pid = raw_input('Enter unique ID number:')
 person = {}
 person['name'] = raw_input('Enter name:')
 person['age'] = raw_input('Enter age:')
 person['phone'] = raw_input('Enter phone number:')
 db[pid] = person
def lookup_person(db):
 """
 Query user for ID and desired field, 
 and fetch the corresponding data 
 from the shelf object
 """
 pid = raw_input('Enter unique ID number:')
 temp = db[pid]
 field = raw_input('Please enter name, age or phone:')
 field.strip().lower()
 print field.capitalize() + ': ', temp[field]
def print_help():
 print 'The avaliable commands are:'
 print 'store :Stores infomation about a person'
 print 'lookup :Looks up a person form ID number'
 print 'quit :Save changes and exit'
 print '? :Prints this message'
def enter_command():
 cmd = raw_input('Enter command(? for help):')
 cmd = cmd.strip().lower()
 return cmd
def main():
 database = shelve.open('database')
 # database stores in current directory
 try:
 while True:
 cmd = enter_command()
 if cmd == 'store':
 store_person(database)
 elif cmd == 'lookup':
 lookup_person(database)
 elif cmd == '?':
 print_help()
 elif cmd == 'quit':
 return
 finally:
 database.close()
 # Close database in any condition
if __name__ == '__main__':
 main()