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Clear Cache for all Pages within a Page Group

Most client sites I have been on tend to love wizards that hold the users hand through often complex business process / workflows. As a general rule, if I have a 10 step wizard (I generally use 1 page per step) I like to ensure that all 10 pages have their cache cleared as the user enters the wizard to ensure no values from a previous attempt to complete the process are hanging around. This is typically done by enter a comma delimited string of all the page numbers you wish to clear the cache of upon branching from page to page. In an ideal world, what I wanted to do was take advantage of the fact that I had taken to time to put all 10 pages into a page group and clear the cache of ALL pages contained within. Furthermore, using this logic, pages can come and go from the page group without the need to worry about how this effect my clearing of session state. Pretty cool huh, but wait, "APEX only allows you to enter page numbers and not page group names into the clear cache text
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Oracle VirtualBox... a good thing.

Now as anyone who knows me me will confirm, I have always been a long admirer of VMWare and their suite of excellent virtualisation products. I started with Workstation before switching to Fusion on OS X and finally made the jump to the way cool ESXi a few years back (I blogged about this here ). Recently however, I am finding less and less time to install guest linux OS, configuring it for use with an Oracle Database (or Application Server), making sure all the RPM's, kernel values are correct etc. Yes you can use the Oracle Validated Packages to help simplify this (see Tims comments below for how to obtain these) but what I really value these days is the simplest configuration for home / home office use that is pretty much turn on and play. After a quick trawl of the Virtual Appliances section of the VM Market Place, I was left wanting until I remembered that Oracle were now dabbling in the Virtual Machine space. After a quick dl of VirtualBox (their virtualisation offering)
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Oracle, APEX and Longevity!

I have just read the latest Statement of Direction from Oracle ( download here ) and there are some comforting statements from Oracle about there long term commitment to Application Express. For those like me who have been using APEX since the early days, this is good news as it represents a very clear intent that Oracle are very serious about APEX as key development framework. Nice read! Cheers Oracle.
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We're Hiring

We are looking for an APEX developer for an initial 3 month contract with definite scope for long term extension for a role in Hampshire (UK). Candidates must be SC cleared or willing to undergo clearance to work on a UK MoD site. Any interested parties, please send me an up to date copy of your CV with availability and rate to: duncanmein@gmail.com
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Native String Aggregation in 11gR2

A fairly recent requirement meant that we had to send a bulk email to all users of each department from within our APEX application. We have 5000 records in our users table and the last thing we wanted to do was send 5000 distinct emails (one email per user) for both performance and to be kind on the mail queue / server. In essence, I wanted to to perform a type of string aggregation where I could group by department and produce a comma delimited sting of all email address of users within that department. With a firm understanding of the requirement, so began the hunt for a solution. Depending on what version of the database you are running, the desired result can be achieved in a couple of ways. Firstly, the example objects. CREATE TABLE app_user (id NUMBER ,dept VARCHAR2 (255) ,username VARCHAR2(255) ,email VARCHAR2(255) ); INSERT INTO app_user (id, dept, username, email) VALUES (1,'IT','FRED','fred@mycompany.com'); INSERT INTO app_user (id, dept, username, em
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A Right Pig's Ear of a Circular Reference

If you have ever used a self referencing table within Oracle to store hierarchical data (e.g. an organisations structure), you will have undoubtedly used CONNECT BY PRIOR to build your results tree. This is something we use on pretty much every project as the organisation is very hierarchy based. Recently, the support cell sent the details of a recent call they received asking me to take a look. Looking down the call, I noticed that the following Oracle Error Message was logged: "ORA-01436: CONNECT BY loop in user data" A quick look at the explanation of -01436 and it was clear that there was a circular reference in the organisation table i.e. ORG_UNIT1 was the PARENT of ORG_UNIT2 and ORG_UNIT2 was the PARENT of ORG_UNIT1 . In this example, both ORG_UNITS were the child and parent of each other. Clearly this was an issue which was quickly resolved by the addition of a application and server side validation to prevent this from re-occurring. The outcome of this fix was
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Pen Test Tool for APEX

Just a quick plug for a cool Penetration Test tool that we have been using on-site for a few months now. The application is called: Application Express Security Console and developed by a company called Recx Ltd This can be used to identify areas of you APEX applications that are vulnerable to: SQL Injection, XSS as well as inadequate access control etc. It kindly suggests ways in which the vulnerability can be addressed as well. We have built the use of this into our formal release process now and has definitely proved value for money to organisation.
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