Informix Error -948

Reasons / Common Causes

-948 fires when RENAME INDEX (or an equivalent) targets a system-generated index backing a constraint (such as the index automatically created for a PRIMARY KEY/UNIQUE constraint) — per the official guidance, this simply isn't allowed, and per the official guidance's own framing, no action is needed since there's no legitimate reason to rename it.

1. RENAME INDEX targeting a system-generated constraint index, per the official guidance — the direct, only cause.
2. A misunderstanding that a constraint's backing index can be renamed independently of the constraint itself, when it's managed automatically as part of the constraint.

Solutions / Resolution

1. No action needed, per the official guidance — renaming a system-generated constraint index isn't permitted under any circumstances, so there's no workaround to apply.
2. If a specific index name was actually the goal, name the constraint itself explicitly when creating it, since a named constraint's backing index typically takes on a name derived from (or configurable via) the constraint definition, rather than trying to rename the index after the fact.

Examples

The disallowed attempt

RENAME INDEX orders_pkey_idx TO orders_id_idx;
-- -948: orders_pkey_idx is a system-generated constraint index

Diagnostic Checks

1. Confirm whether the index being renamed backs a constraint (query sysconstraints for an idxname matching the index) before attempting the rename.

Related Errors / Related Topics

• -584 — "Cannot rename system catalog." A related renaming restriction, for sys* catalog tables rather than constraint indexes.
• -585 — "Cannot rename column in system catalog." Same family, for catalog columns.

No workaround exists — a constraint's backing index can't be renamed; name the constraint itself appropriately when creating it instead.