Duncan Mein's Blog

In one of our Applicaitons, the table DEPT contains a self referncing join (Pigs Ear) as it models our organsational department hierarchy. For example: CREATE TABLE DEPT ( DEPT_ID NUMBER NOT NULL ,PARENT_ID NUMBER ,DEPT_NAME VARCHAR2 (100) NOT NULL ,EMPLOYEES NUMBER NOT NULL ,CONSTRAINT DEPT_PK PRIMARY KEY (DEPT_ID) ,CONSTRAINT DEPT_FK01 FOREIGN KEY (PARENT_ID) REFERENCES DEPT (DEPT_ID) ); INSERT INTO DEPT VALUES (1,NULL,'IT', 100); INSERT INTO DEPT VALUES (2,1,'DEVELOPMENT', 12); INSERT INTO DEPT VALUES (3,1,'SUPPORT', 15); INSERT INTO DEPT VALUES (4,1,'TEST', 25); INSERT INTO DEPT VALUES (5,2,'PL/SQL', 2); INSERT INTO DEPT VALUES (6,2,'Java', 1); INSERT INTO DEPT VALUES (7,2,'SQL', 11); INSERT INTO DEPT VALUES (8,2,'C++', 3); INSERT INTO DEPT VALUES (9,4,'Functional', 3); INSERT INTO DEPT VALUES (10,4,'Non Functional', 5); COMMIT; A quick tree walk using CONNECT BY PRIOR shows you the Parent / Child rel

There is a really cool JavaScript function in Apex called: $f_CheckFirstColumn that allows you to Check / Uncheck all checkboxes that exist in the 1st column position of a Tabular Form / Report. To implement this, all you need do is add the following HTML to the Column Heading of the 1st Column in your Tabular Form (i.e. the Checkbox Column): <input type="Checkbox" onclick="$f_CheckFirstColumn(this)"> Check out an example here

Some of my colleagues are working on a project where bandwidth is massively limited (64k). One suggestion to increase application response time was to use MOD_GZIP (an open source compressor extension to Apache) to compress the outbound HTTP traffic. The only drawback is that MOD_GZIP is not supported by Oracle. Since we are using Oracle Application Server, Web Cache achieves exactly the same by simply adding a compression rule to Web Cache for the URL Regular Expression /pls/apex/.*$ We noticed that without any compression of the HTTP outbound traffic, our test page took 30 seconds to fully render on a 64k link. Turning on compression reduced the rendering time to 7 seconds. Very impressive. Navigating through an application with compression turned on was noticeably quicker than one without compression. To test if your outbound HTTP traffic is compressed, I would grab the Live HTTP Headers extension to Firefox and you are looking for a line like: Content-Encoding: gzip in the outbound

I noticed in one of the comments of Dimitri Gielis articles that Jornica pointed out a script called apxXEpwd.sql I ran this as the SYS user and sure enough, it allows you to reset the ADMIN password for the internal workspace. This script can be found in the root apex directory that you download from OTN. Very useful when you forget what that password is!

I will be honest and admit that I have not been SQL Developers biggest fan since it's release a few years ago. Having always used 3rd party products such as TOAD and PL/SQL Developer, I found certain things a little irritating and not overwhelmingly obvious when forced to use SQL Developer. Recently however, I found an absolute god send of a feature in SQL Developer and that was the ability to import / export APEX applications. This means that the Web GUI for such actions is no longer required. Very simply, you connect to your parsing schema's database account via SQL Developer, right click on the Application Express tree directory and select Import Application. This opens a simple wizard and off you go. One other cool feature of this is that you can open the details window and see exactly what your import is doing, something that is not possible when using the web GUI. Download SQL Developer from: OTN

Just upgraded from APEX 3.1 to 3.1.1 on an Oracle Enterpise Linux 4 Update 4 platform. Intall took: 5:39 and termintaed without error. The patch can be downloaded from metalink (patch number 7032837) All in all, a very simple upgrade and now onto the task of regression testing our current 3.1 apps

One of the really nice features of APEX is the ability to hide / show regions when editing item or page attributes. This is really useful if you have to update the same attribute for multiple items. If you want to implement this type of approach on a page you simply need to: Create a New Region Template Either create a new region template (or copy an existing one) and add a DIV tag with the id="XXX#REGION_STATIC_ID#" around the Definition Template. Don’t forget to close the DIV at the end of the template. In this example I copied our region called “Reports Region” and named it “Reports Region 680 Width (Static ID)” Add the following JavaScript to your Page Header: view Create several regions on your page and assign a unique Static ID i.e. REGION1, REGION2 etc. Set the Region Template to the one you created in the 1. Create a button for each Region you defined in the previous stage and add the following JavaScript call as the URL target of each button: javascript:hideDiv(‘XXXR