----- Original Message -----
Sent: Monday, May 31, 2004 5:56 PM
Subject: Re: [DUG] Temporary Tables &
Interbase / Firebird
Robert,
I think IB 7.1 supports temporary tables,
but I have never found a good reason to use them in FB.
A dBase app is necessarily going to be
very different from one that works with either IB or FB, so you are going to
find that you have to re-think alot of the things that you do.
Stored procedures often help fill the void
when you think that you need a temp table, but the FB/IB language is so rich
that you can often get away without having to even think in terms of temp
tables.
I've converted a whole bunch of apps from
Paradox/dBase to IB/FB, and have found that the best solution is to re-think
the way that you want to access the data. A good tool that can show you
not only query plans, but also number of reads is essential. Sometimes a
full table scan in IB/FB is more efficient than trying to jump through hoops
ensuring that the index that you think is the best is the one
used.
Stuff that looks like it would suck
performance-wise in Paradox or dBase is often very fast when you let the
server do all of the work. Also, if you brush up on using joins, you can
make the server respond much faster than you could ever get a flat-file db to
respond.
Lots of people come unstuck when trying to
use sub-selects in queries. These will always run slow, and can almost
always be re-written as joins which run quickly, but the join syntax to avoid
sub-selects is often not available in dbAccess methods like the
BDE.
There are some cool functions (such as
coalesce) which are available in FB (but not IB) which can remove sub-selects
& make your query faster, but unfortunately they also tie you to a
specific engine. I like to use the "break" keyword in my FB databases,
but it doesn't work in IB.
If you give us specific examples, I'm sure
that members of the community can show you how to translate what you want to
do in dBase to what you should ask a FireBird server to do.
HTH
Trevor
----- Original Message -----
Sent: Monday, May 31, 2004 4:25
PM
Subject: [DUG] Temporary Tables &
Interbase / Firebird
Hi
As you may have gathered we are moving from
Dbase to Firebird. An app we have makes some temporary (dbase) tables
and after processing disposes of them. I know we can create tables in
FB / IB on the fly but we are reluctant to risk polluting our database with
these temporary tables. Any suggestions greatly appreciated
:)
Rob Martin
Software
Engineer
phone 03 377 0495
fax 03 377 0496
web www.chreos.com
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