Sort results on app or database side?

Question

I'd like to think that this is a bit trickier than it might first appear. We have some queries that use ORDER BY, and our database guy is telling us to take them out and do them on the web app side to cut down on Oracle 10g's use of the TEMP table. Here's an example of a frequently run query that populates a quick access select box of their address book entries:
SELECT ReceiverID FROM ADDRESSBOOK WHERE AccountNbr = ? ORDER BY UPPER(ReceiverID)We realized that ORDER BY is probably redundant there since the pair key consists of the AccountNbr and ReceiverID, so since it'll use the index they'll come across already sorted. However, when you go searching, you have queries like this, and even more complicated ones as well:
SELECT ReceiverID, CompanyName FROM ADDRESSBOOK WHERE AccountNbr = ? AND UPPER(CompanyName) LIKE UPPER(?) ORDER BY UPPER(CompanyName)In that case, we need to sort, either in the database or on the application side. Typically, the results per account number are around 200 or less, but sometimes it's in the thousands. I've always thought you're supposed to make the database do stuff like this, but if the database is having to go out to disk to use the TEMP table, then maybe in this case it could be better to sort the ResultSet in Java...I was happy to find out that String already has a Comparator for that, so you can write:
Collections.sort(myList, String.CASE_INSENSITIVE_ORDER)However, on the main address book page, they see about five fields of each entry, and they can sort by any of the five fields. So, say the field they want to sort by is CompanyName. Then I'll have to put all the CompanyNames into a List and also into a HashMap where they're a key to the rest of the fields, and then sort the List and pull the CompanyNames out one by one to get the rest of the fields whose info needs to go on the same line on the webpage. In other words, this seems to be the reason for using ORDER BY on the database side in the first place, so please correct me if I'm wrong...

Answer 1

You're not wrong. Databases are designed and optimized to do exactly what you're doing; a dba that tells you otherwise would be suspect in my opinion.