学生信息管理系统———Python+MySQL

1.需求分析

实现对学生信息的管理，学生具有姓名，学号，年龄三个属性

2.系统功能

1.创建一个学生信息表

2.添加一个学生信息

3.删除一个学生信息

4.修改一个学生信息

5.查找所有学生信息

6.删除一个学生信息表

3.关系模型

student(Name,Email,Age)

4.E-R图

5.代码：

import pymysql

def menu():
    print('欢迎使用学生信息管理系统!')
    print('*'*30)
    print('1.创建一个学生信息表')
    print('2.添加一个学生信息')
    print('3.删除一个学生信息')
    print('4.修改一个学生信息')
    print('5.查找所有学生信息')
    print('6.删除一个学生信息表')
    print('*'*30)

def connection():
    try:
        db = pymysql.connect(host='localhost',
                             user='root',
                             password='521666',
                             database='lc',
                             charset='utf8')
        print('数据库连接成功!')
    except pymysql.Error as e:
        print('数据库连接失败'+str(e))
    db.close()

def CreateTable():
    db = pymysql.connect(host='localhost',
                         user='root',
                         password='521666',
                         database='lc',
                         charset='utf8')
    cur = db.cursor()
    sql = 'create table if not exists student(Name varchar(20) not null,Email varchar(20),Age int)'
    cur.execute(sql)
    db.close()

def Insert():
    db = pymysql.connect(host='localhost',
                         user='root',
                         password='521666',
                         database='lc',
                         charset='utf8')
    cur = db.cursor()
    sql = 'insert into student value(%s,%s,%s)'
    Name = input('请输入学生姓名:')
    Email = input('请输入学生学号:')
    Age = input('请输入学生年龄:')
    value=(Name,Email,Age)
    try:
        cur.execute(sql,value)
        db.commit()
        print('数据插入成功!')
    except pymysql.Errot as e:
        print('数据插入失败!'+e)
        db.rollback()
    db.close()

def deletedata():
    db = pymysql.connect(host='localhost',
                         user='root',
                         password='521666',
                         database='lc',
                         charset='utf8')
    cur = db.cursor()
    sql = 'delete from student where Name = %s'
    value = input('请输入要删除的学生的姓名:')
    try:
        cur.execute(sql,value)
        db.commit()
        print('数据删除成功!')
    except pymysql.Error as e:
        print('数据删除失败'+e)
        db.rollback()
    db.close()

def update():
    db = pymysql.connect(host='localhost',
                         user='root',
                         password='521666',
                         database='lc',
                         charset='utf8')
    cur = db.cursor()
    num = input('请输入数字:(1.修改名字,2.修改学号,3.修改年龄)')
    if num == '1':
        sql = 'update student set Name=%s where Name=%s'
        Before = input('请输入修改之前的学生姓名:')
        After = input('请输入修改之后的学生姓名:')
    if num == '2':
        sql = 'update student set Email=%s where Name=%s'
        Before = input('请输入要修改信息的学生的姓名:')
        After = input('请输入修改之后的学生学号:')
    if num == '3':
        sql = 'update student set Age=%s where Name=%s'
        Before = input('请输入要修改信息的学生的姓名:')
        After = input('请输入修改之后的学生年龄:')
    value=(After,Before)
    try:
        cur.execute(sql,value)
        db.commit()
        print('数据更新成功!')
    except pymysql.Error as e:
        print('数据更新失败'+e)
        db.rollback()
    db.close()

def Find():
    db = pymysql.connect(host='localhost',
                         user='root',
                         password='521666',
                         database='lc',
                         charset='utf8')
    cur = db.cursor()
    sql = 'select * from student'
    try:
        cur.execute(sql)
        results = cur.fetchall()
        for row in results:
            name = row[0]
            email = row[1]
            age = row[2]
            print('Name:%s Email:%s Age:%s' %(name,email,age))
    except pymysql.Error as e:
        print('数据查询失败'+e)
        db.rollback()
    db.close()

def Delete():
    db = pymysql.connect(host='localhost',
                         user='root',
                         password='521666',
                         database='lc',
                         charset='utf8')
    cur = db.cursor()
    sql = 'drop table if exist student'
    cur.execute(sql)
    print('表删除成功!')
    db.close()

def main():
    connection()
    menu()
    while True:
        number = input('请输入数字:')
        if number == '1':
            CreateTable()
        if number == '2':
            Insert()
        if number == '3':
            deletedata()
        if number == '4':
            update()
        if number == '5':
            Find()
        if number == '6':
            Delete()
        if number >= '7':
            print('感谢使用本系统!')
            break

main()