Subject RE: [IBDI] Re: Firebird 1
Author Paulo Gaspar
Answer inline:

> -----Original Message-----
> From: Ed Malloy [mailto:edm@...]
> Sent: Tuesday, June 05, 2001 9:02 PM
> Hi All,
> ...
> AND, I am totally lost on this idea of ROWNUM. How can we have ROWNUM
> in a relational database? We are not guaranteed any ordering of the raw
> data. Am I missing something.....

The ROWNUM is just a "magic" column that is added to the resultset when
this one is generated as the result of some query. So, it is built on the
fly as the result is being built, after the data was joined, filtered,
sorted, etc.

> However, I don't see any problem... Wouldn't we just read All of the
> data into a data structure in memory and assign row numbers to this
> stucture and supply the data sets to the various pages from here. Is it
> critical that these data are not "live?" Couldn't that be solved by
> alowing the user to update the data at any time? what's the problem.

My previous posting explains why I see no gain to the complexity and
memory/processing costs of such approach. The range/ROWNUM approach gets
me what I want in a simple way with the cost of some repeated queries.
I that cost lower (it does not happen that often) than the cost of code
complexity/memory/processing that I would have to pay for each request
when using a caching scheme.

> ed

Have fun,
Paulo Gaspar