Informix Error -4164: The variable is too complex a type to be used in an assignment statement.

Reasons / Common Causes

-4164 fires when a variable's type doesn't support assignment — per the official guidance, you can't assign a value (other than the non-value NULL) to a BYTE/TEXT variable, and you can't assign any value to an ARRAY variable.

1. Assigning a non-NULL value to a BYTE/TEXT variable, per the official guidance — the first named case.
2. Assigning any value to an ARRAY variable as a whole, per the official guidance — the second named case.

Solutions / Resolution

1. For BYTE/TEXT variables, assign only NULL, or use the appropriate BLOB-loading mechanism for actual content.
2. For ARRAY variables, assign individual elements by index instead of the array as a whole.

Examples

Assigning a literal to a BYTE variable

DEFINE photo BYTE
LET photo = "some data"
-- -4164: BYTE variables cannot be assigned non-NULL literals this way

Corrected

LET photo = NULL

Diagnostic Checks

1. Check the type of every assignment target, and confirm BYTE/TEXT targets are only assigned NULL, and ARRAY targets are assigned by individual element.

Related Errors / Related Topics

• -4091 — "Cannot assign to or refer to an array as a whole. Use indexing to refer to individual elements." A closely related error, covering the same array-assignment restriction specifically.

A variable's type (BYTE/TEXT/ARRAY) doesn't support this assignment — assign NULL for BLOBs, or assign individual elements for arrays.