Posted by csimam on 09/02/07 15:18

Hello,

I'd like to start by saying I'm not a DBA, rather I am a Java
developer. But I'm learning more and more about database design, and
it's very interesting.

Here is the general issue I'm facing:

Which one is better?
1. To perform aggregate queries on data, and use that data to home in
and perform more detailed analysis? This gives result sets that are
potentially filled with columns that contain the aggregate data
repeated across many rows.

2. To perform the aggregate query once, and then hit the database
again for a detailed analysis, and return the detailed analysis
results in an order that is easily cross-correlated with the original
aggregate data? This means running the aggregate query essentially
twice, just the second time it is hidden as a subquery.

Now I realize this is a very general question, and I have made
assumptions that a junior DBA does (e.g. in the second option, the
aggregate query must be run again - perhaps this is false?).

Do I need to give an example? It seems to me that you senior DBA's
would run across this a lot; I myself am finding these issues as they
crop up very fascinating.

Thanks for any opinions in advance. I will be happy to give an example
if needed.

- C

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