Someone asked me today if APEX could remember input values for specific page items. For example if you have a page with report parameters could APEX remember the report parameters that the user last used the next time they logged in?

Note: Please read comments below as APEX does support this out of the box on an individual item basis. This solution is to make the option configurable for large applications.

APEX doesn't support this out of the box, however it does have some great features which can enable you to do this. You can use cookies for this but I wanted to make the solution work no matter where the user was accessing the application from.

To make things a bit more difficult, I don't want to remember all item values on a page so I must be able to control which items are "remembered" and which items aren't. I can do this by using a naming convention in my items, however I don't want to rename all my page items (I already have a lot of them). Instead I decided to create a table which will list all the items a user can remember.

You can try the demo here (follow the instructions on the page).

CREATE TABLE tapex_remember_page_item(
application_id NUMBER NOT NULL,
page_id NUMBER NOT NULL,
item_name VARCHAR2(255) NOT NULL);

-- You don't need to add a UK, however it may be a good idea.
ALTER TABLE tapex_remember_page_item ADD(
  CONSTRAINT tapex_remember_page_item_uk1
  UNIQUE (application_id, page_id, item_name));

-- Since I name all my APEX items in uppercase, just do this as an extra precaution
CREATE OR REPLACE TRIGGER trg_tapex_remember_pg_itm_buir
  BEFORE UPDATE OR INSERT
  ON tapex_remember_page_item
  FOR EACH ROW
BEGIN
  :NEW.item_name := UPPER (:NEW.item_name);
END;
/

INSERT INTO tapex_remember_page_item
            (application_id, page_id, item_name)
     VALUES (20195, 1800, 'P1800_DEPTNO');

INSERT INTO tapex_remember_page_item
            (application_id, page_id, item_name)
     VALUES (20195, 1800, 'P1800_MIN_SAL');            

For this example we'll store the values as APEX Preferences, however you could easily create your own preferences table to manage your data. I think they're several advantages to managing the preferences in your own table, however if you have a small application with a limited number of users then I'd recommend using the APEX_UTIL preference options

Create 2 Application Processes:

AP_GET_PAGE_ITEM_PREFS On Load: Before Header (page template header)

DECLARE
BEGIN
  FOR x IN (SELECT item_name
              FROM tapex_remember_page_item
             WHERE :app_page_id = page_id
               AND :app_id = application_id) LOOP
    apex_util.set_session_state (p_name      => x.item_name,
                                 p_value     => apex_util.get_preference (p_preference     => x.item_name,
                                                                          p_user           => :app_user
                                                                         )
                                );
  END LOOP;
END;

AP_SET_PAGE_ITEM_PREFS On Submit: After Page Submission - After Computations and Validations

DECLARE
BEGIN
  FOR x IN (SELECT item_name
              FROM tapex_remember_page_item
             WHERE :app_page_id = page_id
               AND :app_id = application_id) LOOP
    apex_util.set_preference (p_preference => x.item_name, p_value => v (x.item_name), p_user => :app_user);
  END LOOP;
END;

For those of you that are curious APEX Preferences are stored in : apex_030200.wwv_flow_preferences$ where apex_030200 is the schema name for APEX (could also be called flows_xxxxxx)