Informix Error -786

Reasons / Common Causes

-786 fires when the surviving (target) table of an ALTER FRAGMENT ... ATTACH is itself nonfragmented or hash-fragmented, and its own existing data isn't included in the ATTACH clause's table list — per the official guidance, in this specific case the surviving table's existing fragment must be named in the attach list too, so the server knows where to position it within the resulting fragmentation scheme.

1. The target table is nonfragmented (a single storage location) or hash-fragmented, per the official guidance — for these two specific fragmentation states, the target's own existing data needs explicit positioning within the new scheme.
2. The ATTACH clause lists only the new table(s) being added, omitting the target table itself, per the official guidance — this omission is exactly what -786 flags for these specific starting states.

Solutions / Resolution

1. Include the surviving table itself in the ATTACH clause's table list, per the official guidance, alongside the new table(s) being attached:

   ALTER FRAGMENT ON TABLE orders ATTACH orders, orders_2025;
   

2. Confirm whether the target table is nonfragmented or hash-fragmented, since per the official guidance this requirement is specific to those two starting states — other fragmentation strategies (expression-based, range) may not need the target listed this way.

Examples

The disallowed attempt (target omitted)

-- orders is currently nonfragmented
ALTER FRAGMENT ON TABLE orders ATTACH orders_2025;
-- -786: orders itself must also appear in the ATTACH list

Corrected — include the target table too

ALTER FRAGMENT ON TABLE orders ATTACH orders, orders_2025;

Diagnostic Checks

1. Check the target table's current fragmentation state (nonfragmented or hash-fragmented), and if so, confirm it's included in the ATTACH clause's own list.

Related Errors / Related Topics

• -782 — "Attached table is fragmented." A related ATTACH restriction, about the table being newly attached rather than the surviving target table's own listing requirement.
• -783 — "Cannot attach because of incompatible schema." A related ATTACH restriction, on schema/LBAC compatibility rather than the attach list's composition.

Specific to a nonfragmented or hash-fragmented target — include the target table itself in the ATTACH clause alongside the new table(s).