CREATE TABLE tb_commands
(
    cmd_id INTEGER NOT NULL,
    cmd_type INTEGER DEFAULT 1 NOT NULL, -- 1 SELECT, 2 EXEC, 3 SP SELECT, 4 SP EXEC
    cmd_sql BLOB SUB_TYPE 1,
    cmd_memo BLOB SUB_TYPE 1,     
    CONSTRAINT pk_commands PRIMARY KEY (cmd_id)
);

SET TERM ^ ;
CREATE TRIGGER TR_commands_BI FOR tb_commands ACTIVE
BEFORE INSERT POSITION 0
AS
DECLARE VARIABLE vNO INTEGER;
BEGIN
    vNO = GEN_ID("SQN_ID",1);
    IF(NEW.cmd_id IS NULL) THEN 
    BEGIN 
        NEW.cmd_id = vNO; 
    END
END^
SET TERM ; ^