How to connect Python to Mysql to implement a book lending system-Mysql Tutorial-php.cn

Table structure of database

We need three tables here, a user table, a book table and a borrowing table. Note that our database is named bbs (book borrow system)

1. User table

How to connect Python to Mysql to implement a book lending system

2. Book table

How to connect Python to Mysql to implement a book lending system

bookname: book title
author: author
booknum: book number
bookpress: publisher
bookamoun: Number of books

3. Borrowing table

How to connect Python to Mysql to implement a book lending system

##id:borrowing number
borrowname:borrower
borrowbook: Borrowing book
bookid: Book number is the same as the book list booknum
borrowamoun: Borrowing quantity
borrowdate: Borrowing date
borrowback: Returning date

Python program

1. Main program: book lending system.py

# _*_ coding:utf-8 _*_
import pymysql
import db_event
import book_manage


while True:
    print("欢迎使用图书借阅系统\
          [1]登陆 [2]注册 [3]退出")
    choice = int(input("请输入您要进行的操作（数字）："))
    if choice == 1:
        name = input("请输入用户名：")
        login_status=db_event.user_login(name)
        if login_status==1:
            book_manage.manage(name)
        else:
            print("登陆失败")
            continue
    elif choice==2:
        create_user = db_event.user_create()
        print("用户创建成功，您创建的用户信息如下：/n\
              姓名：%s 年龄：%d 性别：%s 密码：%s" % (create_user[0], create_user[1], create_user[2], create_user[3]))
    elif choice==3:
        exit()
    else:
        print("无效操作！")
        continue

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2. Book management information: book_manage.py

import db_event

def manage(name):
    while True:
        print("欢迎进入图书系统\n\
    [1]查询图书 [2] 借阅图书 [3]捐赠图书 [4]归还图书 [5]退出")
        num = int(input(&#39;输入您的选择：&#39;))
        if num == 1:
            db_event.book_select()
        elif num == 2 :
            chos=int(input("请选择[1]借阅 [2]续借 [3]查询借阅信息 [4]退出"))
            if chos==1:
                db_event.book_borrow(name)
            elif chos==2:
                db_event.borrow_again()
            elif chos==3:
                db_event.borrow_info_select(name)
            elif chos==4:
                continue
            else:
                print("无效操作")
        elif num == 3 :
            db_event.book_juanzeng()
        elif num == 4 :
            db_event.book_back()
        elif num == 5 :
            break
        else:
            print("无效输入！")

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3. Database operation: db_event.py

# _*_ coding:utf-8 _*_
import pymysql
import random
import string

def user_login(name):
    db = pymysql.connect("localhost", "ljz", "redhat", "bbs")
    cursor = db.cursor()
    sql = "SELECT name,mima FROM user WHERE name=&#39;%s&#39;" %(name)
    cursor.execute(sql)
    results = cursor.fetchall()

    if results:
        res=results[0]
        for i in range(3):
            mima = input("请输入密码：")
            if mima == res[1]:
                print("登陆成功！")
                login_status = 1
                break
            else:
                login_status=0
                print("密码输入不正确!请重新输入")
        # print(login_status)
        if login_status == 1 :
            return login_status
        else:
            print("您已输入错误密码三次，无法登陆图书借阅系统，欢迎下次使用！")
            login_status = 0
            return login_status
    else:
        login_status = 0
        print("您输入的用户不存在！")
        return login_status
    db.close()
#判断是否登陆成功，1为成功，0为不成功
# login_status=user_login()
# if login_status==1:
#     print("ok")
# else:
#     print("no")
#关闭数据库连接
# curcor.close()
# db.close()

def user_create():
    db = pymysql.connect("localhost", "ljz", "redhat", "bbs")
    cursor = db.cursor()
    name=input("请输入姓名：")
    age=int(input("请输入年龄:"))
    sex=input("请输入性别[M]男 [W]女 ：")
    mima=input("为您的用户设置一个8位数密码：")
    sql = "INSERT INTO user VALUES(&#39;%s&#39;,%s,&#39;%s&#39;,&#39;%s&#39;)" %(name,age,sex,mima)
    cursor.execute(sql)
    db.commit()
    sql1="SELECT * FROM user WHERE name=&#39;%s&#39;" %(name)
    cursor.execute(sql1)
    results=cursor.fetchone()
    return results
    db.close()
#create_user=user_create()
#print("用户创建成功，您创建的用户信息如下：/n\
 #     姓名：%s 年龄：%d 性别：%s 密码：%s" %(create_user[0],create_user[1],create_user[2],create_user[3]))

def book_info_select(x,y):
    db = pymysql.connect("localhost", "ljz", "redhat", "bbs")
    cursor = db.cursor()
    sql = "SELECT * FROM book WHERE %s=&#39;%s&#39;" %(x,y)
    cursor.execute(sql)
    results=cursor.fetchone()
    if results:
        print("书名：%s 作者：%s 书籍编号：%s 出版社：%s 剩余数量：%d " %(results[0],results[1],results[2],results[3],results[4]))
    else:
        print("没有您所要查询的图书")
    db.close()

def book_select():

    a = int(input("输入您要查询的图书关键信息\
            [1]书名 [2]作者 [3]书籍号 [4]出版社"))
    b=""
    if a == 1 :
        b="bookname"
        name=input("请输入要查询的书名：")
        book_info_select(b,name)
    elif a == 2 :
        b="author"
        auth=input("请输入作者名：")
        book_info_select(b,auth)
    elif a == 3 :
        b="booknum"
        num=input("请输入书籍编号")
        book_info_select(b,num)
    elif   a == 4 :
        b="bookpress"
        press=input("请输入出版社：")
        book_info_select(b,press)
    else:
        print("输入有误")
        book_select()

def gen_code(len=8):
    code_str = string.ascii_letters + string.digits
    return &#39;&#39;.join(random.sample(code_str, len))

def book_add(name,auth,press,amount):
    db = pymysql.connect("localhost", "ljz", "redhat", "bbs")
    cursor = db.cursor()
    num=gen_code()
    sql = "INSERT INTO book VALUES(&#39;%s&#39;,&#39;%s&#39;,&#39;%s&#39;,&#39;%s&#39;,%s)" %(name,auth,num,press,amount)
    sql1 = "SELECT booknum FROM book"
    cursor.execute(sql1)
    res = cursor.fetchall()
    list=[]
    for i in res :
        list.append(i)
    try:
        while True:
            if num in list:
                gen_code()
            else:
                cursor.execute(sql)
                db.commit()
                print("图书捐赠成功，谢谢您！")
                break
    except:
        print("输入图书数目错误！")
        db.rollback()
    db.close()

def book_update_add(name,auth,press,amount):
    db = pymysql.connect("localhost", "ljz", "redhat", "bbs")
    cursor = db.cursor()
    sql="UPDATE book SET bookamount=bookamount+%s WHERE bookname=&#39;%s&#39; AND author=&#39;%s&#39; AND bookpress=&#39;%s&#39;" %(amount,name,auth,press)
    try:
        cursor.execute(sql)
        db.commit()
        print("图书捐赠成功，谢谢您！")
    except:
        print("输入图书数目错误！")
        db.rollback()
    db.close()

def book_juanzeng():
    db = pymysql.connect("localhost", "ljz", "redhat", "bbs")
    cursor = db.cursor()
    name=input("请输入您要捐赠的图书书名：")
    auth=input("请输入您要捐赠的图书作者：")
    press=input("请输入您要捐赠的图书的出版社：")
    amount = int(input("输入您要捐赠的数目："))
    sql = "SELECT * FROM book WHERE bookname=&#39;%s&#39;AND author=&#39;%s&#39; AND bookpress=&#39;%s&#39;" %(name,auth,press)
    cursor.execute(sql)
    results=cursor.fetchone()
    if results:
        book_update_add(name,auth,press,amount)
    else:
        book_add(name,auth,press,amount)
    db.close()

def book_if_borrow(booknum,amount):
    db = pymysql.connect("localhost", "ljz", "redhat", "bbs")
    cursor = db.cursor()
    sql = "SELECT bookamount FROM book WHERE booknum=&#39;%s&#39;" %(booknum)
    cursor.execute(sql)
    res = cursor.fetchall()
    if res:
        if res[0][0] >= amount :
    #编号为booknum的书的数量还有，可以借
            return True
        else:
            print("您所需要的编号为%s的书籍当前图书馆只有%d本，不满足您的需求" %(booknum,res[0][0]))
            return False
    else:
        print("查无此书，请确认您的书籍编号！")
        return False
    db.close()

def book_borrow_after(amount,booknum):
    db = pymysql.connect("localhost", "ljz", "redhat", "bbs")
    cursor = db.cursor()
    sql = "UPDATE book SET bookamount=bookamount-%s WHERE booknum=&#39;%s&#39;" %(amount,booknum)
    cursor.execute(sql)
    db.commit()
    db.close()

def borrow_add(name,booknum,amount):
    db = pymysql.connect("localhost", "ljz", "redhat", "bbs")
    cursor = db.cursor()
    days = int(input("请输入您选择借阅的天数（不可超过365天）："))
    sql = "INSERT INTO borrow VALUES(NULL,&#39;%s&#39;,(SELECT bookname FROM book WHERE booknum=&#39;%s&#39;),&#39;%s&#39;,%s,CURDATE(),DATE_ADD(CURDATE(),INTERVAL %s DAY))" %(name,booknum,booknum,amount,days)
    cursor.execute(sql)
    db.commit()

def select_after_borrow(booknum,name):
    db = pymysql.connect("localhost", "ljz", "redhat", "bbs")
    cursor = db.cursor()
    sql2 = "SELECT * FROM borrow WHERE bookid=&#39;%s&#39; AND borrowname=&#39;%s&#39;" % (booknum, name)
    cursor.execute(sql2)
    return cursor.fetchall()

def book_borrow(name):
    db = pymysql.connect("localhost", "ljz", "redhat", "bbs")
    cursor = db.cursor()
    booknum=input("请输入您要借阅的图书编号：")
    amount=int(input("请输入您要借阅的书籍个数："))
    sql1 = "SELECT * FROM book WHERE booknum=&#39;%s&#39;" % (booknum)
    cursor.execute(sql1)
    result = cursor.fetchone()
    res = book_if_borrow(booknum,amount)
    if res:
        print("您要借阅的书籍书名：%s 作者：%s 书籍编号：%s 出版社: %s 当前剩余：%d本 借后剩余：%d本" %(result[0],result[1],result[2],result[3],result[4],result[4]-amount))
        book_borrow_after(amount,booknum)
        #db.commit()
        borrow_add(name,booknum,amount)

        info=select_after_borrow(booknum,name)
        print("以下是您的借阅图书信息，注意借阅号，这将是您还书的凭证！\n\
借阅号：%d 借阅人：%s 借阅图书：%s 图书编号：%s 借阅数量：%d 借阅日期：%s 归还日期：%s" %(info[-1][0],info[-1][1],info[-1][2],info[-1][3],info[-1][4],info[-1][5],info[-1][6]))
        print("借阅成功")
        while True:
            a=int(input("请输入您选择:[1]继续借阅 [2]退出"))
            if a == 1:
                book_borrow(name)
                break
            elif a == 2 :
                break
            else:
                print("无效操作")
    else:
        print("借阅失败")
        while True:
            a=int(input("请输入您选择:[1]继续借阅 [2]退出"))
            if a == 1:
                book_borrow(name)
                break
            elif a == 2 :
                break
            else:
                print("无效操作")
    db.close()

def back_if_over(id):
    db = pymysql.connect("localhost", "ljz", "redhat", "bbs")
    cursor = db.cursor()
    sql = "SELECT * FROM borrow WHERE backdate >= CURDATE() AND id = %s" %(id)
    cursor.execute(sql)
    res=cursor.fetchall()
    if res:
        return True
    else:
        return False
    db.close()

def book_back_update(id):
    db = pymysql.connect("localhost", "ljz", "redhat", "bbs")
    cursor = db.cursor()
    sql = "UPDATE book SET bookamount=bookamount+(SELECT borrowamount FROM borrow WHERE id = %s) WHERE booknum=(SELECT bookid FROM borrow WHERE id = %s)" %(id,id)
    cursor.execute(sql)
    db.commit()
    db.close()

def borrow_back_update(id):
    db = pymysql.connect("localhost", "ljz", "redhat", "bbs")
    cursor = db.cursor()
    sql = "DELETE FROM borrow WHERE id=%s" %(id)
    cursor.execute(sql)
    db.commit()
    db.close()

def book_back():
    db = pymysql.connect("localhost", "ljz", "redhat", "bbs")
    cursor = db.cursor()
    while True:
        id = int(input("请输入您的借阅号："))
        sql1 = "SELECT * FROM borrow WHERE id=%s" %(id)
        cursor.execute(sql1)
        info =cursor.fetchone()
        if info:
            print("以下是您的借阅图书信息，注意借阅号，这将是您还书的凭证！\n\
借阅号：%d 借阅人：%s 借阅图书：%s 图书编号：%s 借阅数量：%d 借阅日期：%s 归还日期：%s" % (info[0], info[1], info[2], info[3], info[4], info[5], info[6]))
            choice=int(input("请确认您的归还借书信息：[1]确认 [2]返回 [3]退出"))
            if choice == 1 :
                #判断是否逾期：
                if back_if_over(id):
                    book_back_update(id)
                    borrow_back_update(id)
                    print("还书成功")
                    break
                else:
                    print("您已逾期，请联系管理员！")
                    break
            elif choice == 2:
                continue
            elif choice == 3 :
                break
            else:
                print("无效输入")
        else:
            print("请输入正确的借阅号")

def borrow_info_again(id,day):
    db = pymysql.connect("localhost", "ljz", "redhat", "bbs")
    cursor = db.cursor()
    sql1 = "SELECT * FROM borrow WHERE id=%s" % (id)
    cursor.execute(sql1)
    info = cursor.fetchone()
    print("以下是您的借阅图书信息:\n\
借阅号：%d 借阅人：%s 续借天数：%d 借阅图书：%s 图书编号：%s 借阅数量：%d 初始借阅日期：%s 归还日期：%s" %(info[0], info[1],day,info[2], info[3], info[4], info[5], info[6]))
    db.close()

def borrow_update_again(id):
    db = pymysql.connect("localhost", "ljz", "redhat", "bbs")
    cursor = db.cursor()
    a=int(input("请输入您的续借天数（不超过31天）:"))
    if a > 31 :
        print("您的借阅天数已超过系统权限，如要借阅，请联系管理员！")
    else:
        sql="UPDATE borrow SET backdate=DATE_ADD(backdate,INTERVAL %s DAY) WHERE id=%s" %(a,id)
        cursor.execute(sql)
        db.commit()
        db.close()
    return a

def borrow_again():
    id=int(input("输入您的借阅号："))
    if back_if_over(id):
        day=borrow_update_again(id)
        borrow_info_again(id,day)
        print("续借成功")
    else:
        print("您已逾期，请先联系管理员再进行操作，谢谢！")

def borrow_info_select(name):
    db = pymysql.connect("localhost", "ljz", "redhat", "bbs")
    cursor = db.cursor()
    sql = "SELECT * FROM borrow WHERE borrowname=&#39;%s&#39;" %(name)
    cursor.execute(sql)
    res=cursor.fetchall()
    if res:
        for i in range(len(res)):
            print("以下是您的第%d条借阅图书信息:\n\
借阅号：%d 借阅人：%s 借阅图书：%s 图书编号：%s 借阅数量：%d 借阅日期：%s 归还日期：%s" % (i+1,res[i][0], res[i][1], res[i][2], res[i][3], res[i][4], res[i][5], res[i][6]))
    else:
        print("您没有借阅图书")
    db.close()

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