Hi

I have a table where an ID is defined as PK with auto-increment.
In the same table, I have ID2 (as FK) and an ID3.
I need to increment ID3 by one for every ID2.
Something like this
Is this possible ?

Thanx

This should be possible in a trigger.

But the main question is why you would want to do this? The PK makes the records unique, adding ID3 makes an alternate key which adds no value to the record (it's just another technical key), it's redundant data.

ID is PK and (ID2,ID3) is unique.

ID2 is used for reference to another table, and ID3 is required to be auto-incremented for every ID2 inserted.

If I can auto-increment for every ID2 inserted then, I can save on PHP code to do this.

Btw, for internal db programming, is Oracle the better choice ? I understand you write programs for your database within Oracle. I've to check with my host to provide the free version of Oracle.

As you are using MySQL V5 then you should be able to make use of MySQL's triggers and stored procedures to do this..
...got to agree with Lexiflex.. it does seem a very peculiar user requirement
if ID2 is incremented then ID3 should also be incremented and noth are a composite FK.

ID2 gets incremented in its own table for which its PK but in this table (where ID1 is PK), ID2 can be any number.

But for every ID2 inserted in this table, ID3 has to be incremented. I want this sequence.

Have you looked at the manual? There is an example which might be what you need to adapt.

http://dev.mysql.com/doc/refman/5.0/...increment.html


see the grp, animal, name example