Oninit
Talk to an expert →

Informix Error -616

-616 A TEXT or BYTE subscript is not allowed within this context.

This UPDATE or INSERT statement specifies a subscripted column of BYTE or TEXT data type as a destination. Subscript notation is not allowed in this context; a BYTE or TEXT (or any other) value must be replaced in full. Revise the statement to assign into whole columns.

Oninit® Troubleshooting Guidance

Reasons / Common Causes

-616 fires when an UPDATE/INSERT statement's destination is a subscripted TEXT/BYTE column (column[start,end]) — per the official guidance, subscript notation is only for reading a portion of a value, not for writing to it; a TEXT/BYTE (or any other) value must be replaced in full.

  1. An UPDATE targeting a subscripted TEXT/BYTE column — per the official guidance, the direct, only cause, treating subscript notation as if it supported partial writes the way it supports partial reads.
  2. A misunderstanding carried over from a language/database where substring assignment is supported, applied to Informix TEXT/BYTE columns where it isn't.
Solutions / Resolution
  1. Revise the statement to assign into the whole column, per the official guidance — replace the entire TEXT/BYTE value rather than a subscripted portion of it.
  2. If only part of the value genuinely needs to change, read the full current value out, modify it at the application level, and write the complete new value back as a whole-column assignment.
Examples
The disallowed attempt
UPDATE documents SET content[1,10] = 'newvalue' WHERE doc_id = 1;
-- -616: subscript notation isn't allowed as an UPDATE destination
Corrected — whole-column assignment
UPDATE documents SET content = 'newvalue' || content[11,500]
  WHERE doc_id = 1;

(reading a subscript on the right-hand side, to build the full replacement value, is fine — it's only the destination side of the assignment that can't be subscripted. Note LENGTH() itself doesn't apply to TEXT/BYTE values, per -575, so an application reading the value's actual length needs to do so through the client library rather than in SQL.)

Diagnostic Checks
  1. Check whether the subscript notation appears on the destination (left) side of an assignment, in an UPDATE ... SET or INSERT, versus the source (right) side where it's allowed.
Related Errors / Related Topics
  • -607 — "Text/Byte subscript error." A related error about subscript syntax itself being malformed, rather than subscript notation being used somewhere it isn't allowed at all.

Subscript notation reads a portion of a value but can't write one — always assign into the whole column.