数学Q1 = 80，Q2 = 90，Q3 = 77

艺术 Q1 = 75，Q2 = 85，Q3 = 80

等等我建立了3个关系表，如下所示学生（ID名级）课程（courseid-coursename）标记（ID-courseid-Q1-Q2-Q3）

我的工作是否正确？因为我会将它升级到SQL，所以我需要知道报表和表单的表和关系是否相同？

Answer 1

好的，但你应该重命名一些字段：课程（id，name），标记（stu_id，course_id，Q1，Q2，Q3）

SQL（我使用PostgreSQL，但我认为其他DBMS类似）

CREATE TABLE students
(
id integer NOT NULL,
fname varchar(20),
lname varchar(20),
grade integer,
PRIMARY KEY (id)
);

CREATE TABLE courses
(
id integer NOT NULL,
name varchar(20),
PRIMARY KEY (id)
);

CREATE TABLE marks
(
stu_id integer REFERENCES students(id),
course_id integer REFERENCES courses(id),
Q1 double,
Q2 double,
Q3 double,
PRIMARY KEY (stu_id, course_id)
);

或

CREATE TABLE marks ( id integer NOT NULL, stu_id integer REFERENCES students(id), course_id integer REFERENCES courses(id), Q1 double, Q2 double, Q3 double, PRIMARY KEY (id) );

希望你的帮助

Answer 2

您应该在标记表中使用复合键。这不会限制你只有3个问题。

用于创建表的Sql Query女士看起来像 -

/****** Object:  Table [dbo].[students]    Script Date: 11/11/2014 16:20:05 ******/
SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

SET ANSI_PADDING ON
GO

CREATE TABLE [dbo].[students](
    [id] [int] NOT NULL,
    [fname] [varchar](20) NULL,
    [lname] [varchar](20) NULL,
    [grade] [int] NULL,
PRIMARY KEY CLUSTERED 
(
    [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

SET ANSI_PADDING OFF
GO




/****** Object:  Table [dbo].[courses]    Script Date: 11/11/2014 16:19:59 ******/
SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

SET ANSI_PADDING ON
GO

CREATE TABLE [dbo].[courses](
    [id] [int] NOT NULL,
    [name] [varchar](20) NULL,
PRIMARY KEY CLUSTERED 
(
    [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

SET ANSI_PADDING OFF
GO



/****** Object:  Table [dbo].[marks]    Script Date: 11/11/2014 16:19:37 ******/
SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

CREATE TABLE [dbo].[marks](
    [stu_id] [int] NOT NULL,
    [course_id] [int] NOT NULL,
    [q_id] [int] NOT NULL,
    [mark] [numeric](18, 0) NOT NULL,
 CONSTRAINT [PK_marks] PRIMARY KEY CLUSTERED 
(
    [stu_id] ASC,
    [course_id] ASC,
    [q_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

ALTER TABLE [dbo].[marks]  WITH CHECK ADD  CONSTRAINT [FK_marks_courses] FOREIGN     KEY([course_id])
REFERENCES [dbo].[courses] ([id])
GO

ALTER TABLE [dbo].[marks] CHECK CONSTRAINT [FK_marks_courses]
GO

ALTER TABLE [dbo].[marks]  WITH CHECK ADD  CONSTRAINT [FK_marks_students] FOREIGN     KEY([stu_id])
REFERENCES [dbo].[students] ([id])
GO

ALTER TABLE [dbo].[marks] CHECK CONSTRAINT [FK_marks_students]
GO

我该如何创建学生标记数据库？

数学Q1 = 80，Q2 = 90，Q3 = 77

2 个答案: