Informix Error -882

Reasons / Common Causes

-882 fires when ALTER TABLE ... ADD ROWIDS targets a non-fragmented table — per the official guidance, this isn't valid because non-fragmented tables already have ROWID by default; there's nothing to add.

1. ALTER TABLE ... ADD a ROWID column attempted on a non-fragmented table, per the official guidance — the direct, only cause; per the official guidance's own closing note, ROWID already exists on non-fragmented tables automatically.
2. A misunderstanding of when ADD ROWIDS is needed at all — this operation is specific to fragmented tables, which (unlike non-fragmented ones) don't automatically carry ROWID.

Solutions / Resolution

1. Don't attempt ADD ROWIDS on a non-fragmented table — per the official guidance, it already has one; the statement is unnecessary, not just disallowed.
2. Confirm the table's fragmentation status before attempting to add ROWID, via sysfragments (fragtype = 'T' rows describe table fragmentation, as opposed to 'I' for index fragmentation) — a table with no matching row here is non-fragmented:

   SELECT strategy, partition FROM sysfragments WHERE fragtype = 'T' AND tabid =
     (SELECT tabid FROM systables WHERE tabname = 'orders');
   

3. If ROWID is genuinely needed on a fragmented table, ADD ROWIDS is the correct operation there — this restriction is specific to non-fragmented tables, which don't need it.

Examples

The disallowed attempt

-- orders is non-fragmented, and therefore already has ROWID
ALTER TABLE orders ADD ROWIDS;
-- -882: unnecessary and disallowed on a non-fragmented table

Diagnostic Checks

1. Confirm whether the table is fragmented, via sysfragments (fragtype = 'T'), before attempting ADD ROWIDS — non-fragmented tables already have it automatically.

Related Errors / Related Topics

• -855 — "Cannot drop rowids on a non-fragmented table." The mirror-image restriction: ROWID can't be dropped from a non-fragmented table either, since it's intrinsic there.
• -856 — "Rowids already exist on table." A related ROWID-management error, about redundantly adding ROWID to a table (fragmented or not) that already has one.

Non-fragmented tables already have ROWID automatically — ADD ROWIDS is unnecessary and disallowed there; it's meant for fragmented tables specifically.