如何将PK添加到DB2中的现有表？

Question

I am facing one problem. I have a table already create in DB2.

CREATE TABLE "DDL12"
(
 "D4_1" decimal(10,0),
 "D4_2" decimal(10,0),
);

I am trying to create a PK on this table as :-

ALTER TABLE "DDL12" ADD CONSTRAINT "Key4" PRIMARY KEY ("D4_1");

But while running the command, I am getting the error saying D4_1 is NULLABLE.

Now, how can I create a PK on this table?

Thanks

Answer 1

Yes, this is due the fact, that your database "could have" rows having NULL value in that non PK column right now.

So first set the column to NOT NULL (+ make sure having a unique value in all rows) and then set the primary key with the command above.

You can change a column to not NULL like this:

ALTER TABLE "DDL12"
 MODIFY "D4_1"   decimal(10,0)     NOT NULL;