If I run:

CREATE TABLE CONSUMOS_FARMACIA
(ID_REGISTRO INTEGER NOT NULL,
CANTIDAD_DISPENSADA SMALLINT NOT NULL CHECK(value > 0);

I get:

Dynamic SQL Error.
SQL error code = -901.
Illegal use of keyword VALUE.

But:
CREATE TABLE CONSUMOS_FARMACIA
(ID_REGISTRO INTEGER NOT NULL,
CANTIDAD_DISPENSADA SMALLINT NOT NULL CHECK(CANTIDAD_DISPENSADA > 0);

Works fine.

Why?

Thanks!