Question

我有一个名为Student_Info表的表，Subject_Info表和一个属于每个学生的个人表，其中包含有关该学生的每个主题参数的信息（如主题的名称，他在该主题中得到的标记等）。

Student_Info

+----+----------+    
| Id | Name     |    
+----+----------+    
|  1 | Sam      |        
|  2 | Taylor   |   
|  3 | Rick     |
+----+----------+

Subject_Info

+---------------+    
| Subject_Name  |    
+---------------+    
|  Physics      |        
|  Chemistry    |   
|  Mathematics  |
+---------------+

1_Info

+---------------+-------+    
| Subject_Name  | Marks |     
+---------------+-------|    
|  Physics      |  60   |   
|  Chemistry    |  40   |
|  Mathematics  |  80   |
+---------------+-------+

2_Info

+---------------+-------+    
| Subject_Name  | Marks |     
+---------------+-------|    
|  Physics      |  70   |   
|  Chemistry    |  50   |
|  Mathematics  |  60   |
+---------------+-------+

3_Info

+---------------+-------+    
| Subject_Name  | Marks |     
+---------------+-------|    
|  Physics      |  70   |   
|  Chemistry    |  70   |
|  Mathematics  |  70   |
+---------------+-------+

这里的表1_Info，2_Info，3_Info分别对应于Id = 1，Id = 2，Id = 3的学生。

我的问题是

如果我在Subject_Info表中插入主题名称，我必须在与每个学生对应的所有单独表格中插入相同的主题名称（1_Info，2_Info，3_Info）。

我使用以下查询来获取表名;它工作正常。

SELECT CONCAT(Id, '_Info') FROM Student_Info;

我尝试使用像这样的单个查询来编写它

INSERT INTO (SELECT CONCAT(Id, '_Info') FROM Student_Info) VALUES ('Physics');

但是得到错误。

是否可以在单个查询中执行此操作？

如果是，那么我在哪里做错了？

为每个学生主题相关参数（1_Info，2_Info等）提供我在这里使用的表的名称是一种好方法吗？如果没有，请建议一个好方法。

Answer 1

我认为将信息放在1表中会更容易，例如

Student
+----+--------+    
| Id | Name   |    
+----+--------+    
|  1 | Sam    |        
|  2 | Taylor |   
|  3 | Rick   |
+----+--------+


Subject
+----+-------------+    
| Id | Subject     |    
+----+-------------+    
|  1 | Physics     |        
|  2 | Chemistry   |   
|  3 | Mathematics |
+----+-------------+

Info
+------------+------------+-------+    
| student_id | subject_id | Marks |    
+------------+------------+-------+    
| 1          | 1          | 60    |
| 1          | 2          | 40    |
| 1          | 3          | 80    |
| 2          | 1          | 70    |
| 2          | 2          | 50    |
| 2          | 3          | 60    |
| 3          | 1          | 70    |
| 3          | 2          | 70    |
| 3          | 3          | 70    |
+------------+------------+-------+

INSERT将是

INSERT INTO Student(Name) VALUES('Tom');

INSERT INTO Subject(Subject) VALUES('History');

INSERT INTO Info(4, 4, 80);

编辑：替代方案，这就是我认为的名称＆＃34;第三范式（3NF）＆＃34;

Student
+----+--------+    
| Id | Name   |    
+----+--------+    
|  1 | Sam    |        
|  2 | Taylor |   
|  3 | Rick   |
+----+--------+


Subject
+----+-------------+    
| Id | Subject     |    
+----+-------------+    
|  1 | Physics     |        
|  2 | Chemistry   |   
|  3 | Mathematics |
+----+-------------+

Marks
+----+------+    
| Id | Mark |    
+----+------+    
|  1 | 60   |        
|  2 | 40   |   
|  3 | 80   |
|  4 | 70   |
|  5 | 50   |
+----+------+

Info
+------------+------------+---------+    
| student_id | subject_id | mark_id |    
+------------+------------+---------+    
| 1          | 1          | 1       |
| 1          | 2          | 2       |
| 1          | 3          | 3       |
| 2          | 1          | 4       |
| 2          | 2          | 5       |
| 2          | 3          | 1       |
| 3          | 1          | 4       |
| 3          | 2          | 4       |
| 3          | 3          | 4       |
+------------+------------+---------+

插入到具有从子查询

1 个答案: