一个简单的使用shelve模块的数据库应用程序

shelve模块的详细信息见Python库参考：http://docs.python.org/3/library/shelve.html

直接看代码：

# database.py
import sys, shelve

def store_person(db):
    '''
    Query user for data and store it in the shelf object
    '''
    pid = input('Enter unique ID number:')
    person = {}
    person['name'] = input('Enter name:')
    person['age'] = input('Enter age:')
    person['phone'] = input('Enter phone:')

    db[pid] = person

def lookup_person(db):
    '''
    Query user for ID and desired field, and fetch the corresponding data from the shelf obejct
    '''
    pid= input('Enter ID number:')
    field = input('What would you like to know?(choice option: name,age,phone):')
    field = field.strip().lower()
    print(field.capitalize()+':', db[pid][field])

def print_help():
    print('The available commands are:')
    print('store   :   Stores information about a person')
    print('lookup  :   Looks up a person from ID number')
    print('quit    :   Save changes are exit')
    print('?       :   Prints this message')

def enter_command():
    cmd = input('Enter command(? for help):')
    cmd = cmd.strip().lower()
    return cmd

def main():
    database = shelve.open('D:\\database.dat')
    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()

if __name__ == '__main__':
    main()

简单交互过程：

在硬盘上产生的文件：