Informix Error -9848: Functional key part cannot use a variant function function_name.

Cause and resolution

Functional key part cannot use a variant function function_name.

The function used in a CREATE INDEX statement for a functional key part must be a nonvariant function (that is, it must be created with the NOT VARIANT modifier in the CREATE FUNCTION statement).

Oninit® Troubleshooting Guidance

Reasons / Common Causes

-9848 fires when a functional key part in a CREATE INDEX statement uses a variant function — per the official guidance.

A function created without the NOT VARIANT modifier used as a functional key part, per the official guidance — the direct, only cause.

Solutions / Resolution

Use a nonvariant function — one created with NOT VARIANT in its CREATE FUNCTION statement, per the official guidance.

Examples

A variant function in a functional key

CREATE FUNCTION my_func(a INT) RETURNING INT VARIANT ...;
CREATE INDEX idx1 ON tab(my_func(col));   -- -9848

Corrected

CREATE FUNCTION my_func(a INT) RETURNING INT NOT VARIANT ...;
CREATE INDEX idx1 ON tab(my_func(col));

Diagnostic Checks

Check the function's VARIANT/NOT VARIANT modifier, and change it to NOT VARIANT if it needs to back a functional index.

Related Errors / Related Topics

-9843 — "Invalid number of arguments for functional key." A related functional-key validity error, on argument count rather than the function being variant.
-9844 — "Invalid function function_name used in a functional key." The general invalid-functional-key-function error this is a specific case of, for variant functions.

A functional key part used a variant function, which isn't allowed — mark the function NOT VARIANT.