triggers

I posted a video a couple of days ago showing a trigger mechanism to customize the capture of DDL that is issued on your database. The aim here is to be more generous with letting developers execute DDL on their Development databases, whilst still having a thorough record of the changes that are occurring. Of course, it goes without saying, which is why I am saying it

• DBA
• ddl
• sys_context
• triggers
• Uncategorized

Yes, you heard me correctly. If you have got one trigger on a table, then you might be surprised to find that perhaps having a second one will be a better option. Then again, I also love the sweet scent of a clickbaity, inflammatory blog post title to draw the readers in so you’ll just have to read on to see which is true.

Yeah…try saying that blog post title 10 times in a row as fast as you can

But since we’re talking about doing things fast, this is just a quick post about a conversation I had a twitter yesterday about the WHEN clause in a trigger.

That is an easy benchmark to whip up – I just need a couple of tables, each with a simple a trigger differing only by their usage of the WHEN clause.  Here is my setup:

There was a time, many moons ago when CLOB, BLOB and BFILE did not exist as data types. So if you had anything longer than a few kilobytes of data to store, you had to use a LONG or a LONG RAW.  But those data types came with all sorts of restrictions and frustrations, and we all embraced the improvements that the LOB data types brought in Oracle 8.  But of course, we carry a lot of that historical “baggage” in the data dictionary.

This question came to me over Twitter, so I thought I’d whip out a quick post on it

Yes, we do implement the IDENTITY column via a sequence.  (Digression – I think this is a smart thing to do.  After all, we’ve had sequences for 20 years, so we know how they work, they are mature, tested, and rock solid, so why invent something new?)

This question came in on AskTom, yielding a very interesting result when it comes to DDL triggers. To set the scene, I’ll first create a table called T which is just a copy of SCOTT.EMP

I’ve recently put a couple of new articles about old subjects on the website. In both cases, the articles were initiated by forum questions, but the explanations became too painful in the format of a forum post so they graduated into articles…

• UDEV SCSI Rules Configuration In Oracle Linux 5 : For those of you that like to follow my Virtual RAC guides, but don’t like using ASMLib, you can use this article and replace ASMLib with UDEV.
• Database Triggers Overview : This is really a primer on database triggers. I’ve focussed mostly on simple DML triggers, since this is what the vast majority of trigger-related questions I’m asked relate to. Consider it the “minimum” you should know before you write a database trigger.

Cheers

Tim…