Wednesday, 18 February 2015

The most frequently abused feature in APEX

Today I participated in the Scott's survey:

and there was one really interesting question:

"What do you think is most frequently abused? (and why)"

If APEX has any week points than it is definitely the fact that you can place your code almost everywhere. Especially PL/SQL chunks of code. If I start counting and list all the places it will be a very long list:

  • Page Read Only and Cache Page Condition
  • Region Conditional Display and Read Only Condition
  • Buttons Conditional Display
  • Items Conditional Display
  • Items Source value or expression
  • Items Post Calculation Computation
  • Items Default value
  • Items Conditional Display and Read Only Condition
  • Computations
  • Processes on Submit, on Load, on Demand
  • Validations and Validation Conditions
  • ...and yes, Dynamic Actions as my favorite.

  • There is of course more but I will stop counting here. If you start working with APEX this is great - you will easily get on target and have an application up and running in no time. A little bit of code here, a little bit there and there we go.

    This problem becomes obvious if you application is more than just a small and temporary solution shared between a couple of people. As an application grows it will start suffering from performance issues. Furthermore it will be hard to maintain it. It will have a dozens of complex pages with many items, many computations and processes, conditional buttons, validations and dynamic actions. If you practice writing anonymous PL/SQL blocks and you paste those wherever it is possible, your code will become redundant and slow. You will probably repeat the same code many times on your page. This means, your pages will require more processing time than they should. I would even go so far and say this is almost as bad as putting your business logic into triggers. Have you ever had a chance to debug such applications (and you didn't know the code was placed there)?

    The possibility to have so many options is of course great and useful. But it doesn't mean you should use all of the options. The other thing important to know is that you should never write anonymous PL/SQL blocks in your applications. Never! Whenever you need to use PL/SQL, you should use packages and place your code there. The probability that you will then repeat your code is quite low and for sure your application will run much faster.

    My proposal for the future version of APEX would be to have a subtitle for each of those containers saying "Handle with care" and providing some explanations why. I am serious here. Really.

    Alert Function

    In APEX you will probably use javascript alert function in many cases by saying:

    alert ('some message');

    The popup box you get looks a bit strange and outdated. As an alternative to this you may use this function call:

    function get_alert (p_message,p_id) {$("<div/>", { "html":p_message}).attr({"title":"Error has occurred!"}).dialog({
    buttons:{"Go to Error":function(){$(this).dialog("close");
    }); }

    As you can see in this example, you can add additional functions to this alert box in order to do something after closing of the alert message. You can choose to display the alert as a modal window as well.


    Tuesday, 17 February 2015

    APEX Jobs

    Alle, die eine Beschäftigung mit Oracle APEX suchen, sollten hier reinschauen:

    Joel's Blog

    Auch einige Stellenangebote aus Deutschland und Schweiz.

    Wednesday, 4 February 2015

    APEX 5.0 - Run Applications in New Tabs

    If you are using Firefox you will probably have an issue with running pages from APEX Builder 5.0 in new Tabs. Now, the links are working differently and normally clicking at button "Save and Run Page" will open a new window. In order to get it opened in a new tab, you will need a plugin Tab Mix Plus. Once you have it, you will need to change the settings there as shown in the screenshots below.