触发器上的 SQL ALTER TABLE

Question

I have a database with 2 tables that look like :

  TABLE_1                         TABLE_2
ID      NAME                     ID      object1       object2                

1      object1                   1        TRUE          FALSE
2      object1                   2        TRUE          TRUE
2      object2

I want that for each new Object on TABLE_1, it add a column on TABLE_2. And for each new ID on TABLE_1, it add a new Occurence on TABLE_2 (but I know how to do "only" this one).

For exemple with INSERT INTO TABLE_1 values(1,"object3"); I want

  TABLE_1                    TABLE_2
ID      NAME               ID      object1       object2       object3               

1      object1             1        TRUE          FALSE         TRUE
2      object1             2        TRUE          TRUE          FALSE
2      object2                    
1      object3

and with INSERT INTO TABLE_1 values(3,"object2);

  TABLE_1                    TABLE_2
ID      NAME               ID      object1       object2       object3               

1      object1             1        TRUE          FALSE         TRUE
2      object1             2        TRUE          TRUE          FALSE
2      object2             3        FALSE         TRUE          FALSE                    
1      object3
3      object2

It's not necessary to fill the added column (I can do it manually).

I tried to do this

CREATE TRIGGER triggTest 
BEFORE INSERT 
ON TABLE_1 
WHEN (NEW.NAME not in (SELECT NAME FROM TABLE_1))
BEGIN 
ALTER TABLE TABLE_2
ADD NEW.NAME BOOLEAN
END;

But it didn't work... Can you help me ? (And sorry if my english isn't perfect)

Answer 1

It looks like you need more tables to achieve what you want.

Table IDs should be unique. "TABLE_1" IDs that are not unique should be kept in another table as Primary Keys, then your "TABLE_1" table could reference that other table containing those IDs as ForeignKeys.

Your "TABLE_2" table looks like it should be split into two: one that would contain your "Objects", and one that associates "Objects" and "IDs".

Or is it only a view of "TABLE_1", displayed differently? Then you can just drop it.

Please read about Junction tables , and SQL and Relational databases in general, because you need more knowledge before starting your project.