Martin Widlake's Yet Another Oracle Blog

Extra session at OUG Ireland – Oracle Lego. March 12, 2015

I’m now doing a second session at OUG Ireland 2015. {This is because one of the accepted speakers had to drop out – it sometimes happens that, despite your best intentions, you can’t make the conference and it is better to let them know as soon as you can, as they did}. This will be a talk called “Oracle Lego” and it is one I put together a couple of years ago when I decided to try and do more introductory talks – talks aimed at those who are not {yet} experts and who I think tend to get ignored by most conference and user group agenda. So it is aimed at those new to oracle or experts in other areas who have never really touched on the subject.

“Oracle Lego” is about the basics of database design. I have a personal soap box I occasionally get on that very little real database design seems to occur these days. There are exceptions, but often the database design seems to be a quick brain-dump of what the developers or business analysts know they need to store information about and the first-cut set of tables gets created – and then endlessly modified as the development rolls on.

Guess what, we don’t build houses, cars, ships, bridges or garden sheds like that – and there is a reason. If you build things piecemeal as you go along and with bits you either have to hand or have to quickly get, you end up with a pretty poor shed. In fact you don’t end up with a shed, you end up with a shack. With a leaking roof and a door that hits the potting table when you open it. I don’t want a shack and I never, ever want to go over a bridge or sail in a ship built “on the hoof” like that!

Further, just as with a proper architectural or engineering design, a database design does not fix the solution in stone, there is still scope for modification. A bespoke house plan gets tweaked and modified as you do the build and you realise what can be improved when you see it – but you do not suddenly decide to dig out a basement and change from wood walls to stone when you have already constructed the ground floor! I’ve seen database “designs” like this.

There is also more to doing a database design than coming up with tables that hold the records we want to store: We might want to consider if storing similar things in the same table could be better than a table for each “type” of something; How we index those tables and relate them together can have a huge impact on how easy it is to get the data out and store it in the first place; The expected volume and life cycle of the data may require us to consider eg archiving; The very-much-ignored aspect of physical placement of data and clustering of data.

You can spend weeks dedicated to learning about database design – but you can also learn a lot in 60 minutes, ie the basics. And it really is like Lego – once you know the basics you can build up a really complex design. And you learn stuff doing it (and turning it into a real system), just like you do the first time you build a Lego robot (or dog or house or car or bridge or spaceship or whatever). So the second time you build your Lego robot you use the same design basics and layer on top what you learnt last time.

So that is the aim of this talk, the basics of database design.

The strange thing is, last time I did this talk I asked the audience how much database design they did. Every single one of them was already an experienced and capable database designer! So why had they come to this intro talk? They had three reasons:

1. It was the only talk on database design at the conference, and one more than they were used to getting.
2. They had picked up their database design skills on-the-job and thought a “reminder” of the basics would be good.
3. It was cold outside and all the other talks appealed less.

So, this time I am hoping some of the audience is new to database design and I get to teach them great stuff they did not know. If it is all experts again, I think I’ll have to retire this particular intro talk, at least for conferences.

As you can see from the agenda grid here, I’ll be talking at 10:15. You can’t link to an abstract of the talk yet, that just needs to be twiddled into place.

Update – Peter Scott stopped by this blog and it prompted a thought. He felt it was too much at a tangent to add as a comment but I felt it was a very valid and valuable point – so check it out over here on his blog.

BTW Pete has started blogging more, on his thoughts and opinions on Data Warehousing. Personally I think it is worth catching them.

{Oh, and in case any lawyers stop by, “Lego” is of course the copyright name of a popular plastic construction toy, made by the Danish company The Lego Group, that children love playing with and adults hate walking on in bare feet. Did anyone not know that?!?! I have no link to The Lego Group and no plastic bricks will form part of my talk.}