I have a table on a iSeries(IBM-i/AS400) which has some constraints. The table is created with SQL like so, with a handful of foreign keys linking from other tables to this table (actual SQL has been a bit obfuscated here):
CREATE TABLE ABCLIB.ABCDE (
DEIDN INTEGER NOT NULL WITH DEFAULT,
DETTL VARGRAPHIC (50) ALLOCATE(25),
DETYP CHAR (1) NOT NULL WITH DEFAULT);
ALTER TABLE ABCLIB.ABCDE ADD PRIMARY KEY (DEIDN);
ALTER TABLE ABCLIB.ABCFG ADD FOREIGN KEY (FGDEK)
REFERENCES ABCLIB.ABCDE (DEIDN)
ON DELETE RESTRICT ON UPDATE RESTRICT;
ALTER TABLE ABCLIB.ABCHI ADD FOREIGN KEY (HIDEK)
REFERENCES ABCLIB.ABCDE (DEIDN)
ON DELETE RESTRICT ON UPDATE RESTRICT;
Now, much later, I will need to alter that table to add a field:
ALTER TABLE ABCLIB.ABCDE ADD COLUMN DEICN VARGRAPHIC (100) ALLOCATE(50)
Which results in this message:
Row or object ABCDE in ABCLIB type *FILE in use.
I have checked and there are definitely no object locks on this table at this time. When I check the joblog, I see this:
Constraint cannot be removed from file Q_AT000000.
Constraint(s) not removed from file Q_AT000000.
File ABCDE in ABCLIB not changed.
Row or object ABCDE in ABCLIB type *FILE in use.
Now, I could of course remove and re-add the constraints in question, but I feel like this should not be necessary. The column I am adding has nothing to do with the constraints. I believe this probably is a result of the fact that in fact OS400 (i5/OS) is not really altering the existing table but instead is creating a new table and copying data in, and that is probably where the pain comes in.
But is there a way to possibly suspend the keys and then resume them after the alter?
(Answers that do not involve doing this with SQL or suggest creating the table differently in the first place are not helpful as they are not applicable here…)
The answer is: I missed the fact that there was a lock on one of the tables that had a foreign key pointing to that table. Or, put more bluntly: I am an idiot!