How to display a plsql error message with dynamic action

Question

I have a plsql that returns a single row and I am executing it by dynamic action, I want to show different error messages by means of APEX_ERROR.ADD_ERROR in case there is no value. Apparently, all the code is correct, but in case of error, it does not show any message.

note: the dynamic action is by pressing a key Condition on the client side javascript = // Enter key this.browserEvent.which === 13 do not submit page.

I do not know if the approach is wrong and you can achieve a better way.

        declare
        l_serie number;
        l_codigo number;
        l_product_name varchar2(500);
        l_precio number;
        l_exists number;

        begin

          select count(*)
          into l_exists
          from (
          select a.ID_INGRESO_SERIE,
                 a.CODIGO_PRODUCTO,
                (select PRODUCT_NAME 
                 from   TBL_PRD_DET
                 where  PRODUCT_ID =a.CODIGO_PRODUCTO ) PRODUCTO,
                (select PRICE
                 from   TBL_SALE_PRICE
                 where PRODUCT_ID=a.CODIGO_PRODUCTO
                 and INVETORY_TYPE=1) PRECIO  
          from   TBL_INGRESOS_DET_SERIES a
          where  ID_INGRESO_SERIE =:P58_CODIGO
          and ESTADO_SERIE = 1
          );


          if l_exists > 0 then

            select a.ID_INGRESO_SERIE,
                   a.CODIGO_PRODUCTO,
                   (select PRODUCT_NAME 
                    from   TBL_PRD_DET
                    where  PRODUCT_ID =a.CODIGO_PRODUCTO ) PRODUCTO,
                   (select PRICE
                    from   TBL_SALE_PRICE
                    where PRODUCT_ID=a.CODIGO_PRODUCTO
                    and INVETORY_TYPE=1) PRECIO  
            into   l_serie,l_codigo,l_product_name,l_precio      
            from   TBL_INGRESOS_DET_SERIES a
            where  ID_INGRESO_SERIE =:P58_CODIGO
            and    ESTADO_SERIE = 1;

            APEX_COLLECTION.ADD_MEMBER (
            p_collection_name =>'LISTA_VENTA',
            p_n001            =>l_codigo,--CODIGO
            p_n002            => 1, ---UNIDADES
            p_n003            =>l_precio , ---PRECIO
            p_n004            =>0,   ---DESCUENTO
            p_n005            =>l_serie,---CODIGO SERIE
            p_c001            =>l_product_name,---NOMBRE PRODUCTO
            p_d001            => SYSDATE
            );

          else
            apex_error.add_error (
            p_message => '¡no exit producto!',
            p_display_location => apex_error.c_inline_in_notification);

          end if;
        end;

Answer 1

apex_error package is only relevant to page processing, not interactions with dynamic actions.

You'll need to display message using technique like this https://www.talkapex.com/2018/03/custom-apex-notification-messages/

Perhaps using concepts mentioned here https://community.oracle.com/message/14948411#14948411

Where your process would set a hidden value, then be displayed using the custom API. How re-usable you make this is up to you.