这次用python连接Sqlite数据库来实现一个简单的学生成绩管理系统，因为我的SQL Server数据库好像有点问题，python成功执行SQL语句后SQL数据库却没有发生变化，没有存储到数据；但是把这段代码放到别人的电脑上运行却没有问题。好了，话不多说，直接开始吧。

一、创建数据库和表

Sqlite数据库是一款轻型的嵌入式数据库，占用资源极低，数据处理速度较快，是默认集成在python系统中的数据库。无需配置，import导入sqlite即可进行操作，也可以下载相关的Sqlite客户端进行操作。

首先我们来创建两个表，一个是Account(账号登录表)，一个是GradeTable(学生成绩表)。

import sqlite3
conn = sqlite3.connect(database="SQLite3.db")
#如果数据库不存在，则会在当前位置自动创建.

# 创建Account表
sql="""create table Account
            ( username varchar(20) not null,
            password varchar(30) not null)
        """
conn.execute(sql)
conn.commit()
conn.close()

import sqlite3

conn = sqlite3.connect(database="SQLite3.db")
# 创建GradeTable表
sql="""create table GradeTable
            (Number varchar(20) not null,
            Name varchar(10),
            Chinese varchar(10),
            Math varchar(10),
            English varchar(10) )
        """
conn.execute(sql)
conn.commit()
conn.close()

二、编写程序代码

然后就是源代码了，上面的表创建好后，记得注释掉。这里我创建了两个类，并且对源代码进行了简单的封装。

全部源代码：

import sqlite3
import sys


# conn = sqlite3.connect(database="SQLite3.db")
# # 创建Account表
# sql="""create table Account
#             ( username varchar(20) not null,
#             password varchar(30) not null)
#         """
# conn.execute(sql)
# conn.commit()
# conn.close()

# 创建GradeTable表
# sql="""create table GradeTable
#             (Number varchar(20) not null,
#             Name varchar(10),
#             Chinese varchar(10),
#             Math varchar(10),
#             English varchar(10) )
#         """
# conn.execute(sql)
# conn.commit()
# conn.close()

#账号登录
class Account:

    def __init__(self):
        __conn = sqlite3.connect(database="SQLite3.db")
        self.__conn = __conn

    def __Login(self):
        print("\n-------------- 1.账号登录 --------------")
        self.__cur = self.__conn.cursor()
        self.__user = input("请输入账号：").strip()
        self.__pwd = input("请输入密码：").strip()
        self.__sql = """select count(*) from Account where username=?;"""
        self.__result = self.__cur.execute(self.__sql, (self.__user,))
        self.__st = self.__result.fetchone()
        if self.__user == "" or self.__pwd == "":
            print("账号或密码不得为空!\n")
            self.__Login()
        elif self.__st[0] == False:
            while True:
                self.__num = input("账号不存在!是否选择注册一个新账号?\n1、是；2、否\n")
                if self.__num == "1":
                    self.__Register()
                elif self.__num == "2":
                    self.Main()
                else:
                    self.__num = input("请重新选择：")
        else:
            self.__VerifyLogin(self.__user, self.__pwd)

    def __VerifyLogin(self, user, pwd):
        self.__cur = self.__conn.cursor()
        self.__sql = """select password from Account where username=?;"""
        self.__result = self.__cur.execute(self.__sql, (self.__user,))
        self.__st = self.__result.fetchone()
        if self.__st[0] == self.__pwd:
            print("账号登录成功!\n")
            self.__st = GradeTable()
            self.__st.Main2()
        else:
            print("账号密码错误!\n")
            self.__Login()

    def __Register(self):
        print("\n-------------- 2.账号注册 --------------")
        self.__cur = self.__conn.cursor()
        self.__user = input("请输入账号：").strip()
        self.__pwd = input("请输入密码：").strip()
        self.__repwd = input("请确认密码：").strip()
        self.__sql = "select count(*) from Account where username=?;"
        self.__result = self.__cur.execute(self.__sql, (self.__user,))
        self.__st = self.__result.fetchone()
        while True:
            if self.__user == "":
                self.__user = input("账号不得为空!\n请输入账号：").strip()
            elif self.__pwd == "":
                self.__pwd = input("密码不得为空!\n请输入密码：").strip()
            elif self.__repwd == "" or self.__pwd != self.__repwd:
                repwd = input("请重新确认密码：").strip()
            elif self.__st[0] == True:
                print("该账号已存在!请重新注册!")
                self.__Register()
            else:
                self.__SaveRegister(self.__user, self.__pwd)

    def __SaveRegister(self, user, pwd):
        self.__cur = self.__conn.cursor()
        self.__sql = "insert into Account (username,password) values (?,?);"
        self.__cur.execute(self.__sql, (self.__user, self.__pwd,))
        self.__conn.commit()
        print("账号注册成功!\n")
        self.Main()

    def __Change(self):
        print("\n-------------- 3.修改密码 --------------")
        self.__cur = self.__conn.cursor()
        self.__user = input("请输入账号：").strip()
        self.__oldpwd = input("请输入密码：").strip()
        self.__newpwd = input("请输入新密码：").strip()
        sql = """select count(*) from Account where username=?;"""
        self.__result = self.__cur.execute(sql, (self.__user,))
        self.__st = self.__result.fetchone()
        while True:
            if self.__user == "":
                self.__user = input("账号不得为空!\n请输入账号：").strip()
            elif self.__oldpwd == "":
                self.__oldpwd = input("密码不得为空!\n请输入密码：").strip()
            elif self.__oldpwd == self.__newpwd or self.__newpwd == "":
                newpwd = input("请重新输入新密码：").strip()
            elif self.__st[0] == False:
                print("账号不存在!\n")
                self.Main()
            else:
                self.__VerifyChange(self.__user, self.__oldpwd, self.__newpwd)

    def __VerifyChange(self, user, oldpwd, newpwd):
        self.__cur = self.__conn.cursor()
        self.__sql = """select password from Account where username=?;"""
        self.__result = self.__cur.execute(self.__sql, (user,))
        self.__st = self.__result.fetchone()
        if self.__st[0] == self.__oldpwd:
            self.__SaveChange(self.__user, self.__newpwd)
        else:
            print("账号密码错误!\n")
            self.__Change()

    def __SaveChange(self, user, newpwd):
        try:
            print("账号密码修改成功!\n")
            self.__cur = self.__conn.cursor()
            self.__sql = """update Account set password=? where username=?;"""
            self.__cur.execute(self.__sql, (self.__newpwd, self.__user))
            self.__conn.commit()
            self.Main()
        except:
            print("账号密码修改失败!\n")
            self.Main()

    def __Cancel(self):
        print("\n-------------- 4.账号注销 --------------")
        self.__cur = self.__conn.cursor()
        self.__user = input("请输入账号：").strip()
        self.__pwd = input("请输入密码：").strip()
        self.__sql = """select count(*) from Account where username=?;"""
        self.__result = self.__cur.execute(self.__sql, (self.__user,))
        self.__st = self.__result.fetchone()
        if self.__user == "" or self.__pwd == "":
            print("账号或密码不得为空!\n")
            self.__Cancel()
        elif self.__st[0] == False:
            print("账号不存在!\n")
            self.Main()
        else:
            self.__VerifyCancel(self.__user, self.__pwd)

    def __VerifyCancel(self, user, pwd):
        self.__cur = self.__conn.cursor()
        self.__sql = """select password from Account where username=?;"""
        self.__result = self.__cur.execute(self.__sql, (self.__user,))
        self.__st = self.__result.fetchone()
        if self.__st[0] == self.__pwd:
            self.__DeleteCancel(user)
        else:
            print("账号密码错误!\n")
            self.Main()

    def __DeleteCancel(self, user):
        try:
            cur = self.__conn.cursor()
            sql = """delete from Account where username=?;"""
            cur.execute(sql, (self.__user,))
            self.__conn.commit()
            print("账号注销成功!\n")
            self.Main()
        except:
            print("账号注销失败!\n")
            self.Main()

    def Main(self):
        print("1、账号登录；2、账号注册；3、修改密码；4、账号注销；0、退出.")
        self.__num = input("请输入选择：").strip()
        if self.__num == "1":
            self.__Login()
        elif self.__num == "2":
            self.__Register()
        elif self.__num == "3":
            self.__Change()
        elif self.__num == "4":
            self.__Cancel()
        elif self.__num == "0":
            print("程序已退出!")
            self.__conn.close()
            sys.exit(0)
        else:
            self.Main()

#学生成绩管理类
class GradeTable:
    def __init__(self):
        __conn = sqlite3.connect(database="SQLite3.db")
        self.__conn = __conn

    def __GradeInput(self):
        print("\n------------------ 1.学生成绩输入 -----------------")
        self.__cur = self.__conn.cursor()
        self.__number = input("请输入学生学号：").strip()
        self.__name = input("请输入学生姓名：").strip()
        self.__chinese = input("请输入语文成绩：").strip()
        self.__math = input("请输入数学成绩：").strip()
        self.__english = input("请输入英语成绩：").strip()
        self.__sql = """select count(*) from GradeTable where Number=?;"""
        self.__reslut = self.__cur.execute(self.__sql, (self.__number,))
        self.__st = self.__reslut.fetchone()
        while True:
            if self.__name == "":
                self.__number = input("学生学号不得为空!\n请输入学生学号：").strip()
            elif self.__number == "":
                self.__name = input("学生姓名不得为空!\n请输入学生姓名：").strip()
            elif self.__chinese == "":
                chinese = input("语文成绩不得为空!\n请输入语文成绩：").strip()
            elif self.__math == "":
                self.__math = input("数学成绩不得为空!\n请输入数学成绩：").strip()
            elif self.__english == "":
                self.__english = input("英语成绩不得为空!\n请输入英语成绩：").strip()
            elif self.__st[0] == True:
                print("该学生的成绩信息已输入!\n")
                self.__GradeInput()
            else:
                self.__Input(self.__number, self.__name, self.__chinese, self.__math, self.__english)

    def __Input(self, number, name, chinese, math, english):
        try:
            self.__cur = self.__conn.cursor()
            self.__sql = """insert into GradeTable(Number,Name,Chinese,Math,English) values (?,?,?,?,?)"""
            self.__cur.execute(self.__sql, (self.__name, self.__number, self.__chinese, self.__math, self.__english))
            self.__conn.commit()
            print("学生成绩输入成功!\n")
            self.__GradeOutput()
        except:
            print("学生成绩输入失败!\n")
            self.Main2()

    def __GradeOutput(self):
        print("\n************************* 2.学生成绩输出 *****************************")
        print("-----------------------------------------------------------------------------")
        print("    学号    |    姓名    |    语文    |    数学    |    英语    |    总分    |    平均分    ")
        print("------------------------------------------------------------------------------")
        try:
            self.__cur = self.__conn.cursor()
            self.__sql = """select* from GradeTable"""
            self.__result = self.__cur.execute(self.__sql)
            self.__st = self.__result.fetchall()
            for i in self.__st:
                self.__sum = int(i[2]) + int(i[3]) + int(i[4])
                self.__avg = self.__sum / 3.0
                print("    " + i[0] + "   |   " + i[1] + "    |     " + i[2] + "      |      " + i[3] + "     |      " +
                      i[4] + "     |    " + str(self.__sum) + "    |     " + str(round(self.__avg, 2)) + "  ")
                print("------------------------------------------------------------------------------")
            print()
            self.Main2()
        except:
            print("学生成绩信息输出失败!\n")
            self.Main2()

    def __GradeSearch(self):
        print("\n------------------ 3.学生成绩查询 -----------------")
        print("1、按学生姓名查询；2、按学生学号查询；0、返回.")
        self.__num = input("请输入选择：")
        if self.__num == "1":
            self.__SelectName()
        elif self.__num == "2":
            self.__SelectNumber()
        elif self.__num == "0":
            self.Main2()
        else:
            self.__GradeSearch()

    def __SelectName(self):
        self.__cur = self.__conn.cursor()
        self.__name = input("请输入学生姓名：").strip()
        self.__sql = """select count(*) from GradeTable where Name=?;"""
        self.__result = self.__cur.execute(self.__sql, (self.__name,))
        self.__st = self.__result.fetchall()
        if self.__st[0] == (0,):
            print("查无此人!")
            self.__GradeSearch()
        elif self.__st[0] == (1,):
            self.__OutputName(self.__name)
        else:
            print("该学生姓名有多个!请按学号查询!")
            self.__GradeSearch()

    def __OutputName(self, name):
        print("\n-----------------------------------------------------------------------------")
        print("    学号    |    姓名    |    语文    |    数学    |    英语    |    总分    |    平均分    ")
        print("------------------------------------------------------------------------------")
        try:
            self.__cur = self.__conn.cursor()
            self.__sql = """select * from GradeTable where Name =?;"""
            self.__result = self.__cur.execute(self.__sql, (self.__name,))
            self.__st = self.__result.fetchall()
            for i in self.__st:
                self.__sum = int(i[2]) + int(i[3]) + int(i[4])
                self.__avg = self.__sum / 3.0
                print("    " + i[0] + "   |   " + i[1] + "    |     " + i[2] + "      |      " + i[3] + "     |      " +
                      i[4] + "     |    " + str(self.__sum) + "    |     " + str(round(self.__avg, 2)) + "  ")
                print("------------------------------------------------------------------------------")
            self.__GradeSearch()
        except:
            print("学生成绩查询失败!\n")
            self.__GradeSearch()

    def __SelectNumber(self):
        self.__cur = self.__conn.cursor()
        self.__number = input("请输入学生学号：").strip()
        self.__sql = """select count(*) from GradeTable where Number =?;"""
        self.__result = self.__cur.execute(self.__sql, (self.__number,))
        self.__st = self.__result.fetchall()
        if self.__number == "":
            print("学号不得为空!")
            self.__SelectNumber()
        elif self.__st[0] == True:
            self.__OutputNumber(self.__number)
        else:
            print("该学号不存在!\n")
            self.__GradeSearch()

    def __OutputNumber(self, number):
        print("\n-----------------------------------------------------------------------------")
        print("    学号    |    姓名    |    语文    |    数学    |    英语    |    总分    |    平均分    ")
        print("------------------------------------------------------------------------------")
        try:
            self.__cur = self.__conn.cursor()
            self.__sql = """select* from GradeTable where Number=?;"""
            self.__result = self.__cur.execute(self.__sql, (self.__number,))
            self.__st = self.__result.fetchall()
            for i in self.__st:
                self.__sum = int(i[2]) + int(i[3]) + int(i[4])
                self.__avg = self.__sum / 3.0
                print("    " + i[0] + "   |   " + i[1] + "    |     " + i[2] + "      |      " + i[3] + "     |      " +
                      i[4] + "     |    " + str(self.__sum) + "    |     " + str(round(self.__avg, 2)) + "  ")
                print("------------------------------------------------------------------------------")
            self.__GradeSearch()
        except:
            print("学生成绩查询失败!\n")
            self.__GradeSearch()

    def __GradeChange(self):
        self.__cur = self.__conn.cursor()
        print("\n------------------ 4.学生成绩修改 -----------------")
        self.__number = input("请输入学生学号：").strip()
        self.__name = input("请输入学生姓名：").strip()
        self.__sql = """select count(*) from GradeTable where Number=? and Name=?;"""
        self.__result = self.__cur.execute(self.__sql, (self.__number, self.__name,))
        self.__st = self.__result.fetchone()
        if self.__number == "" or self.__name == "":
            print("学号或姓名不得为空!\n")
            self.__GradeChange()
        elif self.__st[0] == True:
            self.__ChangeNumber(self.__number)
        else:
            print("查无此人!\n")
            self.Main2()

    def __ChangeNumber(self, number):
        print("\n1、语文；2、数学；3、英语；0、返回.")
        self.__num = input("请选择要修改成绩的学科：").strip()
        if self.__num == "1":
            self.__chinese = input("请输入修改后的语文成绩：").strip()
            self.__AlterChineser(self.__num, number, self.__chinese)
        elif self.__num == "2":
            self.__math = input("请输入修改后的数学成绩：").strip()
            self.__AlterMath(self.__num, self.__number, self.__math)
        elif self.__num == "3":
            self.__english = input("请输入修改后的英语成绩：")
            self.__AlterEnglish(self.__num, self.__number, self.__english)
        elif self.__num == "0":
            self.Main2()
        else:
            self.__ChangeNumber(self.__number)

    def __AlterChineser(self, num, number, chinese):
        self.__cur = self.__conn.cursor()
        try:
            self.__sql = """update GradeTable set Chinese=? where Number =?;"""
            self.__cur.execute(self.__sql, (self.__chinese, self.__number))
            self.__conn.commit()
            print("语文成绩修改成功!\n")
            self.__ChangeNumber(number)
        except:
            print("语文成绩修改失败!\n")
            self.__ChangeNumber(self.__number)
        finally:
            self.__ChangeNumber(self.__number)

    def __AlterMath(self, num, number, math):
        try:
            self.__cur = self.__conn.cursor()
            self.__sql = """update GradeTable set Math=? where Number =?;"""
            self.__cur.execute(self.__sql, (self.__math, self.__number))
            self.__conn.commit()
            print("数学成绩修改成功!\n")
            self.__ChangeNumber(self.__number)
        except:
            print("数学成绩修改失败!\n")
            self.__ChangeNumber(self.__number)
        finally:
            self.__ChangeNumber(self.__number)

    def __AlterEnglish(self, num, number, english):
        try:
            self.__cur = self.__conn.cursor()
            self.__sql = """update GradeTable set English=? where Number =?;"""
            self.__cur.execute(self.__sql, (self.__english, self.__number))
            self.__conn.commit()
            print("英语成绩修改成功!\n")
            self.__ChangeNumber(number)
        except:
            print("英语成绩修改失败!\n")
            self.__ChangeNumber(number)
        finally:
            self.__ChangeNumber(number)

    def __DeleteGrade(self):
        print("\n------------------ 5.学生成绩删除 -----------------")
        self.__cur = self.__conn.cursor()
        self.__number = input("请输入学生学号：").strip()
        self.__name = input("请输入学生姓名：").strip()
        self.__sql = """select count(*) from GradeTable where Number=? and Name=?;"""
        self.__result = self.__cur.execute(self.__sql, (self.__number, self.__name,))
        self.__st = self.__result.fetchone()
        if self.__number == "":
            print("学号或姓名不得为空!\n")
            self.__DeleteGrade()
        elif self.__st[0] == True:
            self.__CancelDelete(self.__number)
        else:
            print("查无此人!\n")
            self.Main2()

    def __CancelDelete(self, number):
        try:
            self.__cur = self.__conn.cursor()
            self.__sql = """delete from GradeTable where Number =?;"""
            self.__cur.execute(self.__sql, (self.__number,))
            self.__conn.commit()
            print("学生成绩信息删除成功!\n")
            self.Main2()
        except:
            print("学生成绩信息删除失败!\n")
            self.Main2()

    def Main2(self):
        print("**************************************************************************")
        print("1、学生成绩输入；2、学生成绩输出；3、学生成绩查询；4、学生成绩修改；5、学生成绩删除；6、返回登录界面；0、退出当前程序.")
        print("**************************************************************************")
        self.__num = input("请输入选择：").strip()
        if self.__num == "1":
            self.__GradeInput()
        elif self.__num == "2":
            self.__GradeOutput()
        elif self.__num == "3":
            self.__GradeSearch()
        elif self.__num == "4":
            self.__GradeChange()
        elif self.__num == "5":
            self.__DeleteGrade()
        elif self.__num == "6":
            sd = Account()
            sd.Main()
        elif self.__num == "0" or self.__num == "":
            self.__conn.close()
            print("程序已退出!")
            sys.exit(0)
        else:
            self.Main2()


if __name__ == '__main__':
    st = Account()
    st.Main()

运行效果截图

以上就是全部的操作过程了，仅供大家参考和学习，感兴趣的小伙伴可以来看看。可能还有些不足之处，也欢迎大家多多批评指正。

个人声明：禁止转载！！！严禁抄袭！！如果要引用部分代码，请标明出处！！