Tag: APEX

Disable IE Compatibility Mode

Most places I’ve worked at allow employees to use any of the major browsers to do their work, but mandate an “SOE” that only supports IE, presumably because that generates the most amount of work for us developers. I’d conservatively estimate that 99% of the rendering bugs I’ve had to deal with are only reproducible in IE. (cue one of the thousands of IE joke images… nah, just do a Google Image search, there’s plenty!)

Anyway, we had a number of these rendering issues in Apex on IE8, IE9 and IE10, mainly in edge cases involving some custom CSS or plugins. In some cases I was never able to reproduce the issue until we noticed that the user had inadvertently switched “IE Compatility Mode” on:

iecompatibility1

We told them to make sure the icon was grey, like this:

iecompatibility2

– and most of the issues went away.

Since there’s nothing in our Apex application that requires compatibility mode, we would rather the option not be available at all. To this end, we simply add this code to all the Page templates in the application:

<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">

This is added just after the <head> tag, like this:

iecompatibility3

Now, the compatility button doesn’t appear at all – one less choice for users and less bug reports to deal with:

iecompatibility5

For more information, see this stackoverflow question and read all the answers. Note that it may be better to add this as a header in the response generated by your web server. In our case it was simpler to just add it into the html.

Deploying Apex: showing an “Under Maintenance” web page

systemdown

I’ve added this script to our toolbelt for future upgrades. We have a friendly “System is under maintenance, sorry for any convenience” web page that we want to show to users while we run upgrades, and we want it to be shown even if we’re just doing some database schema changes.

So I took the script from here and adapted it slightly, here’s our version:

declare PRAGMA AUTONOMOUS_TRANSACTION;
  v_workspace CONSTANT VARCHAR2(100) := 'MYSCHEMA';
  v_workspace_id NUMBER;
begin
  select workspace_id into v_workspace_id
  from apex_workspaces where workspace = v_workspace;
  apex_application_install.set_workspace_id (v_workspace_id);
  apex_util.set_security_group_id
    (p_security_group_id => apex_application_install.get_workspace_id);
  wwv_flow_api.set_flow_status
    (p_flow_id             => 100
    ,p_flow_status         => 'UNAVAILABLE_URL'
    ,p_flow_status_message => 'http://www.example.com/system_unavailable.html'
    );
  commit;
end;
/

It uses an autonomous transaction because we want the system to be unavailable immediately for all users while the deployment is running.

Warning: WWV_FLOW_API is an undocumented package so this is not supported.

The opposite script to make the application available again is:

declare PRAGMA AUTONOMOUS_TRANSACTION;
  v_workspace CONSTANT VARCHAR2(100) := 'MYSCHEMA';
  v_workspace_id NUMBER;
begin
  select workspace_id into v_workspace_id
  from apex_workspaces where workspace = v_workspace;
  apex_application_install.set_workspace_id (v_workspace_id);
  apex_util.set_security_group_id
    (p_security_group_id => apex_application_install.get_workspace_id);
  wwv_flow_api.set_flow_status
    (p_flow_id             => 100
    ,p_flow_status         => 'AVAILABLE'
    );
  commit;
end;
/

However, if we run the f100.sql script to deploy a new version of the application, we don’t need to run the “set available” script since the redeployment of the application (which would have been exported in an “available” state already) will effectively make it available straight away.

Tabular Form – set default values with jQuery

tabular-form-default-jquery4

I have a simple tabular form with a numeric “sort order” column. I want the value of this column to be defaulted automatically, based on the maximum value of the rest of the records on the screen. Unfortunately the builtin Apex default type for columns in a tabular form can only be based on an Item, or a PL/SQL expression or function. I didn’t want to make a database call to get the maximum value because the user may have added multiple records which have not yet been saved to the database.

I tried basing the default on a hidden page item which I kept updated based on the values entered, but it seems the tabular form only gets the item’s value on page load and doesn’t re-examine the item’s value when you click the “Add” button. Instead, I had to turn to javascript and jQuery to get the job done.

1. Add a class to the tabular form column by setting the Element CSS Classes column attribute (I’ve used “sortorder” as the class name).

tabular-form-default-jquery2

2. Add a javascript function to the page that searches for all the “sortorder” items, calculates the maximum value and adds 10, and assigns it to the last sortorder item on the page.

function setNextSortOrder() {
  var highest=0;
  $(".sortorder").each(function(){
    if (this.value != "") {
      highest=Math.max(highest,parseFloat(this.value));
    }
  });
  $(".sortorder").last().val(highest+10);
}

tabular-form-default-jquery1

3. Modify the javascript for the “Add” button to call the setNextSortOrder function immediately after adding a row.

javascript:{apex.widget.tabular.addRow();setNextSortOrder();}

tabular-form-default-jquery3

It’s a bit hackish and might not work correctly in some cases but it’ll do for now.

Apex CSV Import: “Data Loading Failed”

If you are using the Apex built-in Data Loading feature to allow your users to upload CSV files, you may have encountered this error.

Data-Loading-Failed
(Note: the error may appear differently in your application as I have built a custom error handling function)

It’s not a particularly useful message, and the logs don’t seem to shed much light on the problem either – reporting only the following:

DATA_LOAD - Final collection is created
...Execute Statement: select 1 from "DEMO"."MY_TABLE" where "RECORD_ID" = :uk_1
Add error onto error stack
...Error data:
......message: Data Loading Failed
......additional_info: ORA-01403: no data found
...
......ora_sqlerrm: ORA-01403: no data found
......error_backtrace:
  ORA-06512: at "APEX_040200.WWV_FLOW_DATA_UPLOAD", line 4115
  ORA-06512: at "APEX_040200.WWV_FLOW_PROCESS_NATIVE", line 213
  ORA-06512: at "APEX_040200.WWV_FLOW_PROCESS_NATIVE", line 262
  ORA-06512: at "APEX_040200.WWV_FLOW_PLUGIN", line 1808
  ORA-06512: at "APEX_040200.WWV_FLOW_PROCESS", line 453

After trial and error I tracked down one potential cause of this error so I thought I’d share it in case it happens again. I’ll probably come across this again later and forget what the solution was and find this article.

In my case (Apex 4.2.4), the problem was caused by an invalid entry in the Column Name Aliases list of values. I was using a custom List of Values so that alternative names for the columns would be automatically mapped without the user having to select them every time. To do this, I had to edit the List of Values directly to add the alternative names; but I had mistyped one of the Return Values which must map to a real column name on the target table. Whenever I picked this column for an import, I’d get the “Data Loading Failed” error message. Correcting the return value resolved the issue.

In order to stop this happening again, I added the following check to my Apex QA script (this is run whenever the application is deployed):

PROMPT Invalid dataload column mappings (expected: none)
SELECT REPLACE(lt.owner,'#OWNER#',USER) AS owner
      ,lt.table_name
      ,le.return_value  AS target_column_not_found
      ,le.list_of_values_name
      ,le.display_value AS col_alias
      ,lt.application_id
      ,lt.application_name
      ,lt.name AS dataload_definition
FROM   apex_appl_load_tables lt
JOIN   apex_application_lov_entries le
ON     le.lov_id = lt.column_names_lov_id
WHERE NOT EXISTS (
  SELECT NULL
  FROM   all_tab_columns tc
  WHERE  tc.owner = REPLACE(lt.owner,'#OWNER#',USER)
  AND    tc.table_name = lt.table_name
  AND    tc.column_name = le.return_value)
ORDER BY lt.name, le.display_sequence;

If the above query returns any rows, it’ll be a problem.

Remove punctuation from string using Javascript

I’m a morning person, and my mind is usually sharpest on Monday or Tuesday mornings, so these are the best times for me to work on fiddly javascript stuff. Today was one of those mornings and here are the results, just in case I want to refer back to them later on.

I had many items dotted around an Apex application where the user is allowed to enter “Codes” – values that must be uppercase and contain no spaces or other punctuation characters – except underscores (_) were allowed.

To make things easier for the user, I wanted the page to automatically strip these characters out when they exit the field, instead of just giving validation errors (Note: I still included the validations, but the javascript just makes the process a bit smoother for the user doing the data entry).

My Apex application already has a global .js file that is loaded with each page, so all I had to do was add the following code to it:

function cleanCode (c) {
  return c.replace(/[^A-Za-z0-9_]/g,"");
}

$(document).ready(function() {

  //automatically remove non-code characters from
  //"edit_code" class
  $( document ).on('change', '.edit_code', function(){
    var i = "#"+$(this).attr("id");
    $(i).val( cleanCode($(i).val()) );
  });

});

EDIT: greatly simplified regexp based on the excellent contribution by Jacopo :)
EDIT #2: corrected, thanks to Sentinel

Finally, on each “Code” page item, I set the following attribute (or append, if other classes have already been added):

HTML Form Element CSS Classes = edit_code

For code items within a tabular form, I set the following column attribute:

Element CSS Classes = edit_code