Display Only vs text fields with "Disabled" attribute set to YES - oracle-apex

I am using APEX 21.2.
The help says that "Display Only" Items do not store session state value and text fields with "Disabled" attribute set to yes do. But I tried to create an after header computation and set the value of a display only item and it worked. Is it wrong information or am I missing something?
Disabled
Specify whether this item is disabled, which prevents end users from changing the value.
A disabled text item still displays with the same HTML formatting, unlike an item type of Display Only, which removes the HTML formatting. Disabled text items are part of page source, which enables their session state to be evaluated. Conversely, display only items are not stored in session state.

I tried to create an after header computation and set the value of a display only item and it worked
Why wouldn't it work? It is you (a developer) who set it using a computation (which works), but end user can't modify its value as it is set to be display only so - users can just look at item's value.

A computation before rendering is always possible, that has nothing to do with session state. This is about how the item behaves on page submit.
With the "Display Only" item type you can control its behaviour on submit. Behaviour is the same for "Text Field" items that have the "Disabled" property set to on.
I did a quick test with a form on the EMP sample data set. Create a after header computation of type expression :P1_SAL + 1.
Test 1: Setting "set on page submit" on. The form renders with the salary item increased by 1. When page is saved, the new salary is saved for the record
Test 2: Setting "set on page submit" off. The form renders with the salary item increased by 1. When page is saved, the new salary is NOT saved for the record
Where did you see this help text ? I don't see anything about session state.

Related

Remove value from popup lov once its selected

I'm trying to create lov in which once the machine is started it should not show in popup lov after submit.
Popup lov sql is as below:
select machineid,machinenm from machinemaster where idlemachine = 'Y';
but the issue is once machine is status change and this query not finding result for the perticular machineid so in lov it shows blank.
Please suggest any workaroud.
First of all, query you posted looks wrong. Generally speaking, list of values' query returns two values in the following order:
display value
return value
We usually display names and return IDs, which means that you'd probably want to use
select machinenm as display_value,
machineid as return_value
from machinemaster
where idlemachine = 'Y';
the issue is once machine is status change ...
How is that statement reflected in query you posted? There's no "status" column nor "change" status itself; where clause says where idlemachine = 'Y' - no status, no "change".
... and this query not finding result for the perticular machineid so in lov it shows blank
I believe that you should set the Display extra values property ON. Help says:
An item may have a session state value which does not occur in the given list of values definition. Select whether this list of values displays this extra session state value. If you choose to not display this extra session state value and there is no matching value in the list of values definition, the first value in the list of values is the selected and displayed value.
If you're seeing the NULL value, it means that you actually set
display extra values to OFF
display null value to ON

Oracle Apex Dynamic action not working for form items

I have a form with items P1_APP and P1_USER.
P.S. P1_USER is select list.
Display John
Return 1
Display Andy
Return 2
I need to disable when user selects John.
When P1_USER = 'John', P1_APP should get disabled which is a multi select list.
I created dynamic action on P1_APP, True Action= Disable,Affected element P1_APP
Client condition : Item =Value
Item= P1_USER
Value= John
However this is not working.
I have used similar logic to disable interactive grid items and was able to do so. Why is this not working for form?
EDIT: In Value now i am putting 1 which is return value for John.
However when i select John. It disables P1_App upon clicking. But remains disabled even when i choose Andy.
This works for me using the following configuration.
Create form and report on EMP - everyone has access to that sample data, it is a good idea to post questions based on that.
In the form P3_DEPTNO is a select list with source
SELECT d.dname, d.deptno FROM dept d
Add a page item to my form P3_APP. This is a select list with "Allow multi selection" enabled. Select list has 2 static values.
Create a dynamic action on change of P3_DEPTNO.
Client side condition: Item = Value
Item: P3_DEPTNO
Value: 30 (note that this is the return value for SALES, not display value)
add true action of "Disable", affected item P3_APP
Click true action and select "Create Opposite Action". Save.
When I run this it work. Selecting SALES in the select list disables the item P3_APP and selecting something else enables it.

How to prepopulate date field based on other date field?

I have 2 date fields in oracle apex, Date1 is mandatory needs to be input by user and Date2 needs to prepopulate as (Date1+2 years) then user clicks the save button to save the values in database.
Then, if user clicks Date2 and change to something else, it should take that value and save.
Eg:
1.User inputs Date1 - 02/07/2019
2.Date2 should automatically populate as - 02/07/2021 but should not be saved in database.
3.User clicks save button to save data.
4.User wants to change Date2 to - 05/10/2019
5.User clicks save to save data.
I tried to set value using dynamic action for step2, but step4 is not working whenever I click save button, it's recalculating back to Date1+2 years.
Please help.
Suppose you have P1_ID (primary key), P1_DATE1 and P1_DATE2 on your form.
Create a dynamic action to set value of P1_DATE2 on change of P1_DATE1. Use PL/SQL Expression as type and PL/SQL Expression
ADD_MONTHS(TO_DATE(:P1_DATE1,'DD/MM/YYYY'),24);
Set "Fire on initialization" to false so it won't recalculate P1_DATE2 when the screen loads for an existing record - that might be the cause of the behaviour you're seeing.
It makes sense that you only want the dynamic action to fire for a new record so you could add a server-side condition in your dynamic action of "ITEM IS NULL" for item P1_ID.

How to write a query based on the Date item, in interactive grid

I have a date field and a interactive grid. I am trying to generate the Interactive grid based on the value inputted in the date field.
I am trying to write the query as below :
select pap.effective_start_date , pap.effective_end_date
from per_all_people_f pap
where :SELECT_DATE between pap.effective_start_date and
pap.effective_end_date
Here, SELECT_DATE is the name of the Date field (datatype Date picker). I am writing a dynamic action on Change of Date field, and refreshing the interactive grid region.
But when I change the value in Date field, it doesn't return any rows.
I have done a similar change where my interactive grid was based on a dropdown. There I had to set the "page action on selection" to Submit, and it worked. But here, since it is a Date field, the "Page Action on selection" property doesn't appear on the page .
Can somebody please suggest, how can I achieve this.
You need to explicitly convert your bind variables, which are treated as strings, to dates.
to_date(:SELECT_DATE)
The format mask will come from the application properties, or you can be explicit with that, too.

Trigger a process (SQL update) when leaving an APEX page

This is a very odd question but i wondered whether it was possible to trigger a process that runs an SQL UPDATE when the user leaves this specific page, either by clicking on the breadcrumb, tabs or back button?
I did setup the process to run on the 'Back' button; however i ran into the problem of: What if s/he clicks on the breadcrumb or a tab instead.
I have searched the net and posting this question was a last resort. I wondered if anyone can point me in the correct direction?
UPDATED POST
Page 1:
Includes a text field and a button. The user enters the category into the text field and clicks on the button to proceed to the next page. The button passes the value in the text field to a text field on Page 2.
Page 2:
Two regions on the page. One region holds information about the category - Category name from the previous page, category description, and the category revision number (which is what i'm trying to get working). The second region is a report that pulls the item name and number that are listed under the category in the category text field. A 'View' link is used on the report to load the edit page for the specific item selected. The 'View' link passes the 'category name' (from the category text field) and the 'item number' from the report to page 3.
Page 3
Two regions are used, first region: Lists the Item number which came from page 2 and name of the item (which i use a simple query to retrieve). In the second region: A report is used with two columns: a list of item properties in column 1, and a text field next to each item property in column 2 to hold the value that can be updated. The 'Apply Changes' button has some PlSql behind which looks for changes and updates where required. It updates the relevant fields that have changed, and it then takes the user back to Page 2 (Page showing user the items listed for the category intitally entered).
I cant increase the category revision on the 'apply changes' button on page 3 because the user may complete edits for items under the same category. So i dont know where i can increase the category revision by 1 per vist to a category. P.s I already increment the revision number for each item by 1 if the info has been changed using the 'apply changes' button on page 3.
One way of doing this is by updating the session state of the page items (without submitting the page as normal) via ajax and by calling an Application Process which updates the table, when called by a javascript onbeforeunload.
Create an Application Process to fire On Demand, named UpdatePageXOnExit or something. In the PL/SQL block of that Application Process, use SQL update commands with the item state of each item on the page that you wish to update; something like the following:
BEGIN
UPDATE table_name SET col1 = :PX_ITEM_1, col2 = :PX_ITEM_2, col3 = :PX_ITEM3, col4 = :PX_ITEM_4, col5 = PX_ITEM_5
WHERE (condition... I would suggest ROWIDs to simplify changes to the
fields of the PK; otherwise you will have to create additional
page items for each field of the PK, then set those items to
the values of the PK when the page loads using a before
header page process, and then use those values in this where
clause like this: where col1 = :PX_ORIGINAL_PK_FIELD_1 AND col2 =
:PX_ORIGINAL_PK_FIELD_2 );
END ;
Go to the page settings for that particular page, and in the JavaScript: Execute On Page Load section, write something like the following:
window.onbeforeunload = updateOnExit;
And in the JavaScript Function and Global Variables Declaration, write something like the following:
function updateOnExit() {
var get = new htmldb_Get(null,&APP_ID.,'APPLICATION_PROCESS=UpdatePageXOnExit',&APP_PAGE_ID.);
get.add('PX_ITEM_1',$x('PX_ITEM_1').value)
get.add('PX_ITEM_2',$x('PX_ITEM_2').value)
get.add('PX_ITEM_3',$x('PX_ITEM_3').value)
get.add('PX_ITEM_4',$x('PX_ITEM_4').value)
get.add('PX_ITEM_5',$x('PX_ITEM_5').value)
gReturn = get.get();
get = null;
// Comment out the following line or not, as per the note in the following paragraph
return 'Are you sure you would like to leave the page?';
}
This last piece is the AJAX that updates the session states of the page items on the page that have been changed on the user's end but that haven't been uploaded to the servers end which normally occurs during page submission. Note: If you comment out the return statement, than there will be no warning box that will allow the user to stay on the page. If that is what you prefer, go for it. If you chose to use the warning box, the ajax will execute the page process even if the user chooses to stay on the page.