CREATE FUNCTION "URX_PUBLIC"."_add_raster_constraint"(cn name, sql text) 
 RETURNS boolean AS 
$BODY$
	BEGIN
		BEGIN
			EXECUTE sql;
		EXCEPTION
			WHEN duplicate_object THEN
				RAISE NOTICE 'The constraint "%" already exists.  To replace the existing constraint, delete the constraint and call ApplyRasterConstraints again', cn;
			WHEN OTHERS THEN
				RAISE NOTICE 'Unable to add constraint: %', cn;
				RAISE NOTICE 'SQL used for failed constraint: %', sql;
				RAISE NOTICE 'Returned error message: % (%)', SQLERRM, SQLSTATE;
				RETURN FALSE;
		END;

		RETURN TRUE;
	END;
	$BODY$
 LANGUAGE 'plpgsql' VOLATILESTRICT ;