Duncan Mein's Blog

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...

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 ...

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.