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Steve Moland wrote:
7. RE: Understanding User Indexes from RPG (Steve Moland) I've used user indexes a number of times to replace run time tables which were used cut down on the time disk "chains" take. I've found the indexes to be much faster than using keyed disk files though I always thought of user indexes as just being the built-in access method that a "chain" in RPG would use.
Steve:User indexes can be faster than CHAINs. But make sure you understand why there's a gain in speed at all.
See: http://publib.boulder.ibm.com/infocenter/iseries/v5r4/index.jsp?topic=/apiref/conIndexCons.htmIn addition to what's shown there, keep in mind that you won't be getting a lot of the support that can appear as "overhead" in DB2. There's no auto-mapping of database fields into program variables. There's no row-locking for 'updates'; if you need locking, you'll do it yourself. Perhaps a number of other things can be listed. In short, these aren't database tables.
*USRIDXs can be handy. I've been using single ones in apps to replace all *DTAARAs by more or less using the data area name as the index value and putting the previous data into the rest of the entry. Since the entries are unformatted, you can put any kind of field-mapping you want in there. Only a single object to manage for ownership, authority, etc.
But they do need some different thinking. Tom Liotta
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