Re: Learn Oracle in three days?

I'll take DB cluefulness for $100, Alex...

"Pablo Sanchez" <pablo_at_dev.null> wrote in message news:<3cdf2e5a_13_at_news.teranews.com>...
> If you're wondering what I believe a hard core database person to
> know, here are some sample questions:
>
> * Do you understand the concept of dense versus non-dense indexes?
Huh? New terms to me - Do you mean "dense" index and "sparse" index, perhaps?

> * Do you understand why databases have a 'data' portion and a 'log'
> portion?

Sure - one word: transactions.

> * Do you understand why the need for checkpointing?
Without a checkpoint, logical logs, err... redo logs are useless - you don't have a point in time where you know how things were for recovery.

> * Do you understand what happens on a DBMS failure and its recovery
> from the log perspective?

Roll forward the uncompleted transactions from the redo log, and roll back the uncommited transactions in the tables.

> * Do you know how piggybacking off of an index can help you? (also
> known as a 'covered query')

Are you are talking about clustering? Or an foreign index? I don't recognize the term - never had a DBA use it in front of me before (inside lingo?)

> * Do you know the I/O characteristics of the:
> - log
> - data

I do now - the oracle concepts guide got into really intimate detail of how all the pieces work.

>
> (these kinda just came quickly)
>
> As for extents, segments and tablespaces, I find these to be one of
> the nice things about Oracle. Perhaps you were being flippant but to
> be able to micro-manage where my data resides on disk and on which
> disks is extremely important to me for performance reasons.

Acutally I'm finding the features of hash joins and partioning described the manuals very interesting. I've never seen the DBAs use them in Informix - they may not exist. (But then again, they there is referential integrity features in Informix and they don't use that either.) From what I've been reading, It seem that in comparison to Informix, Oracle _really_ lets you decide where things go. In reality, I think we should be using more of Oracle at my place, the DBAs here might just be wimps. We do a lot of online engine to data warehouse type stuff where we unload data on one database and load on another (literally). The data migratory features described in the Oracle manuals are very compelling features to me.

> If the above is a bit for you, I'd take a DBA class ASAP. Some
> mangler really did a poor job scheduling the launch of the app.

Now halfway through my time to prepare for this thing, I think I've figured out my bigges hangup with figuring out Oracle: It's not really a database - it's more like an operating system (with a database inside). I think that in my work with it that I treat it like one, it looks looks like it might take me far.

Thanks for the insight,

• MW