可以直接从我的GitHub中获取文档：

一 题目

学生选课系统

二 需求分析

1.根据学生专业学年学期等信息，录入课程完成课程计划

2.根据课程计划，录入任课教师信息3.学生可以根据学年学期等信息，选择课程完成选课要求

三 结构概念设计

计划受众表信息

学生表信息教师表信息课程表信息教学计划表信息任课表信息学生选课表信息

四 ER图（基于三级范式）

这里我遇到一个问题如何设计ER图 和如何根据ER图设计关系逻辑呢？

看了以上这篇 收益很多 可以参考下

五 数据字典

Stdunt表（学生表）

字段名           数据类型         长度            约束            描述字段名    数据类型    长度    约束    描述Student_id    Nvar char    50    主键    学生学号Gender    Nvarchar    50    无    性别Name    Nvarchar    50    无    学生名字category    Nvarchar    50    无    种类

Course表（课程表）

字段名    数据类型    长度    约束    描述course_id    Nvarchar    50    主键    课程号Name    Nvarchar    50    唯一键    课程名mode    Nvarchar    50    无    考核方式Credit    Int        无    学分

each表（教师任课表）

字段名    数据类型    长度    约束    描述Teach_id    Nvarchar    50    主键    任课号Plan_id    Nvarchar    50    外键，组合唯一键    教学计划号Teacher_id    Nvarchar    50    外键，组合唯一键    教师编号

Teacher表（教师表）

字段名    数据类型    长度    约束    描述Teacher_id    Nvarchar    50    主键    教师编号Name    Nvarchar    50    无    教师名Gender    Nvarchar    50    无    性别Student_select表（学生选课表）字段名    数据类型    长度    约束    描述Select_id    Nvarchar    50    主键    选课号Student_id    Nvarchar    50    外键，组合唯一键    学生编号Teach_id    Nvarchar    50    外键，组合唯一键    排课编号

Administrator表

字段名    数据类型    长度    约束    描述administrator    Nvarchar    50        管理员号password    Nvarchar    50        密码

Plan表（教学计划表）

字段名    数据类型    长度    约束    描述plan_id    nvarchar    50    主键    教学计划号audience_id    nvarchar    50    外键，组合唯一键    计划受众号course_id    nvarchar    50    外键，组合唯一键    课程号

audience表（计划受众表）

字段名    数据类型    长度    约束    描述auience_id    nvarchar    50    主键约束    计划受众idacademy    nvarchar    50    无    学院major    nvarchar    50    无    专业grade    nvarchar    50    无    年级semester    Int        无    学期

六 数据库定义语句

CREATE DATABASE [Student_Select]GOUSE [Student_Select]GO/****** Object:  Table [dbo].[Teacher]    Script Date: 06/27/2018 10:37:01 ******/SET ANSI_NULLS ONGOSET QUOTED_IDENTIFIER ONGOCREATE TABLE [dbo].[Teacher](    [teacher_id] [nvarchar](50) NOT NULL,    [name] [nvarchar](50) NULL,    [gender] [nchar](10) NULL, CONSTRAINT [PK_Teacher] PRIMARY KEY CLUSTERED (    [teacher_id] ASC)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]) ON [PRIMARY]GOINSERT [dbo].[Teacher]([teacher_id], [name], [gender]) VALUES (N'1', N'1', N'1         ')INSERT [dbo].[Teacher]([teacher_id], [name], [gender]) VALUES (N'2', N'2', N'2         ')/****** Object:  Table [dbo].[Course]    Script Date: 06/27/2018 10:37:01 ******/SET ANSI_NULLS ONGOSET QUOTED_IDENTIFIER ONGOCREATE TABLE [dbo].[Course](    [course_id] [nvarchar](50) NOT NULL,    [name] [nvarchar](50) NULL,    [mode] [nvarchar](50) NOT NULL,    [credit] [nvarchar](50) NULL, CONSTRAINT [PK_Course] PRIMARY KEY CLUSTERED (    [course_id] ASC)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY], CONSTRAINT [IX_Course] UNIQUE NONCLUSTERED (    [name] ASC)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]) ON [PRIMARY]GOEXEC sys.sp_addextendedproperty @name=N'MS_Description', @value=N'考核方式' , @level0type=N'SCHEMA',@level0name=N'dbo', @level1type=N'TABLE',@level1name=N'Course', @level2type=N'COLUMN',@level2name=N'mode'GOINSERT [dbo].[Course]([course_id], [name], [mode], [credit]) VALUES (N'1', N'1', N'1', N'1')INSERT [dbo].[Course]([course_id], [name], [mode], [credit]) VALUES (N'2', N'2', N'2', N'2')/****** Object:  Table [dbo].[audience]    Script Date: 06/27/2018 10:37:01 ******/SET ANSI_NULLS ONGOSET QUOTED_IDENTIFIER ONGOCREATE TABLE [dbo].[audience](    [audience_id] [nvarchar](50) NOT NULL,    [academy] [nvarchar](50) NULL,    [major] [nvarchar](50) NULL,    [grade] [nvarchar](50) NULL,    [semester] [int] NULL, CONSTRAINT [PK_audience] PRIMARY KEY CLUSTERED (    [audience_id] ASC)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]) ON [PRIMARY]GOEXEC sys.sp_addextendedproperty @name=N'MS_Description', @value=N'受众ID' , @level0type=N'SCHEMA',@level0name=N'dbo', @level1type=N'TABLE',@level1name=N'audience', @level2type=N'COLUMN',@level2name=N'audience_id'GOEXEC sys.sp_addextendedproperty @name=N'MS_Description', @value=N'学院' , @level0type=N'SCHEMA',@level0name=N'dbo', @level1type=N'TABLE',@level1name=N'audience', @level2type=N'COLUMN',@level2name=N'academy'GOEXEC sys.sp_addextendedproperty @name=N'MS_Description', @value=N'年级' , @level0type=N'SCHEMA',@level0name=N'dbo', @level1type=N'TABLE',@level1name=N'audience', @level2type=N'COLUMN',@level2name=N'grade'GOEXEC sys.sp_addextendedproperty @name=N'MS_Description', @value=N'学期' , @level0type=N'SCHEMA',@level0name=N'dbo', @level1type=N'TABLE',@level1name=N'audience', @level2type=N'COLUMN',@level2name=N'semester'GOINSERT [dbo].[audience]([audience_id], [academy], [major], [grade], [semester]) VALUES (N'1', N'1', N'1', N'1', 1)INSERT [dbo].[audience]([audience_id], [academy], [major], [grade], [semester]) VALUES (N'2', N'2', N'2', N'2', 2)/****** Object:  Table [dbo].[Administrator]    Script Date: 06/27/2018 10:37:01 ******/SET ANSI_NULLS ONGOSET QUOTED_IDENTIFIER ONGOCREATE TABLE [dbo].[Administrator](    [administrator] [nvarchar](50) NULL,    [password] [nvarchar](50) NULL) ON [PRIMARY]GO/****** Object:  Table [dbo].[Student]    Script Date: 06/27/2018 10:37:01 ******/SET ANSI_NULLS ONGOSET QUOTED_IDENTIFIER ONGOCREATE TABLE [dbo].[Student](    [student_id] [nvarchar](50) NOT NULL,    [gender] [nchar](10) NULL,    [name] [nvarchar](50) NULL,    [category] [nvarchar](50) NOT NULL, CONSTRAINT [PK_Student] PRIMARY KEY CLUSTERED (    [student_id] ASC)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]) ON [PRIMARY]GOINSERT [dbo].[Student]([student_id], [gender], [name], [category]) VALUES (N'1', N'1         ', N'1', N'1')INSERT [dbo].[Student]([student_id], [gender], [name], [category]) VALUES (N'2', N'2         ', N'2', N'2')/****** Object:  Table [dbo].[Plan]    Script Date: 06/27/2018 10:37:01 ******/SET ANSI_NULLS ONGOSET QUOTED_IDENTIFIER ONGOCREATE TABLE [dbo].[Plan](    [plan_id] [nvarchar](50) NOT NULL,    [audience_id] [nvarchar](50) NOT NULL,    [course_id] [nvarchar](50) NOT NULL, CONSTRAINT [PK_Plan] PRIMARY KEY CLUSTERED (    [plan_id] ASC)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY], CONSTRAINT [IX_Plan] UNIQUE NONCLUSTERED (    [audience_id] ASC,    [course_id] ASC)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]) ON [PRIMARY]GOINSERT [dbo].[Plan]([plan_id], [audience_id], [course_id]) VALUES (N'1', N'1', N'1')INSERT [dbo].[Plan]([plan_id], [audience_id], [course_id]) VALUES (N'2', N'2', N'2')/****** Object:  Table [dbo].[Teach]    Script Date: 06/27/2018 10:37:01 ******/SET ANSI_NULLS ONGOSET QUOTED_IDENTIFIER ONGOCREATE TABLE [dbo].[Teach](    [teach_id] [nvarchar](50) NOT NULL,    [plan_id] [nvarchar](50) NULL,    [teacher_id] [nvarchar](50) NULL, CONSTRAINT [PK_Teach] PRIMARY KEY CLUSTERED (    [teach_id] ASC)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY], CONSTRAINT [IX_Teach_1] UNIQUE NONCLUSTERED (    [teach_id] ASC,    [plan_id] ASC)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]) ON [PRIMARY]GOINSERT [dbo].[Teach]([teach_id], [plan_id], [teacher_id]) VALUES (N'1', N'1', N'1')INSERT [dbo].[Teach]([teach_id], [plan_id], [teacher_id]) VALUES (N'2', N'2', N'2')/****** Object:  Table [dbo].[Student_Selete]    Script Date: 06/27/2018 10:37:01 ******/SET ANSI_NULLS ONGOSET QUOTED_IDENTIFIER ONGOCREATE TABLE [dbo].[Student_Selete](    [selete_id] [nvarchar](50) NOT NULL,    [student_id] [nvarchar](50) NOT NULL,    [teach_id] [nvarchar](50) NOT NULL, CONSTRAINT [PK_Student_Selete] PRIMARY KEY CLUSTERED (    [selete_id] ASC)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY], CONSTRAINT [IX_Student_Selete_1] UNIQUE NONCLUSTERED (    [student_id] ASC,    [teach_id] ASC)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]) ON [PRIMARY]GO/****** Object:  ForeignKey [audience_id]    Script Date: 06/27/2018 10:37:01 ******/ALTER TABLE [dbo].[Plan]  WITH CHECK ADD  CONSTRAINT [audience_id] FOREIGN KEY([audience_id])REFERENCES [dbo].[audience]([audience_id])GOALTER TABLE [dbo].[Plan] CHECK CONSTRAINT [audience_id]GO/****** Object:  ForeignKey [course_id]    Script Date: 06/27/2018 10:37:01 ******/ALTER TABLE [dbo].[Plan]  WITH CHECK ADD  CONSTRAINT [course_id] FOREIGN KEY([course_id])REFERENCES [dbo].[Course]([course_id])GOALTER TABLE [dbo].[Plan] CHECK CONSTRAINT [course_id]GO/****** Object:  ForeignKey [plan_id]    Script Date: 06/27/2018 10:37:01 ******/ALTER TABLE [dbo].[Teach]  WITH CHECK ADD  CONSTRAINT [plan_id] FOREIGN KEY([plan_id])REFERENCES [dbo].[Plan]([plan_id])GOALTER TABLE [dbo].[Teach] CHECK CONSTRAINT [plan_id]GO/****** Object:  ForeignKey [teacher_id]    Script Date: 06/27/2018 10:37:01 ******/ALTER TABLE [dbo].[Teach]  WITH CHECK ADD  CONSTRAINT [teacher_id] FOREIGN KEY([teacher_id])REFERENCES [dbo].[Teacher]([teacher_id])GOALTER TABLE [dbo].[Teach] CHECK CONSTRAINT [teacher_id]GO/****** Object:  ForeignKey [student_zhujian]    Script Date: 06/27/2018 10:37:01 ******/ALTER TABLE [dbo].[Student_Selete]  WITH CHECK ADD  CONSTRAINT [student_zhujian] FOREIGN KEY([student_id])REFERENCES [dbo].[Student]([student_id])GOALTER TABLE [dbo].[Student_Selete] CHECK CONSTRAINT [student_zhujian]GO/****** Object:  ForeignKey [teach_zhujian]    Script Date: 06/27/2018 10:37:01 ******/ALTER TABLE [dbo].[Student_Selete]  WITH CHECK ADD  CONSTRAINT [teach_zhujian] FOREIGN KEY([teach_id])REFERENCES [dbo].[Teach]([teach_id])GOALTER TABLE [dbo].[Student_Selete] CHECK CONSTRAINT [teach_zhujian]GO

七 数据库关系图

最后贴一下朋友的数据库ER图和逻辑设计，是仓库管理系统，我觉得也可以参考：

ER图：

逻辑图：