Betreft: RE: [AccessD] ..Performance ADO - DAO ..

Henry Simpson hsimpson88 at hotmail.com
Tue Oct 21 13:39:34 CDT 2003


Even worse, if you refresh the global while a procedure in the call stack 
uses the same global and there has been a change in the collections, you are 
open to some bizarre results.  Running a Workspaces transaction in 97 seems 
to leave a previously initialized global database variable as an object but 
not pointing to a database.  I had to rewrite a fair bit of old code when I 
started using transactions since I was getting errors from using a global 
database object.  For my first couple of years with Access I was quite happy 
with a Global database variable, the performance it provided, and the fact 
that I didn't need to dimension, open, close and set to nothing in a great 
many procedures.  I never did find out exactly why transactions caused me so 
much difficulty and it is possible it was merely because I didn't start with 
a separate database object.  That experience did awaken my awareness of the 
potential consequences of nested procedures potentially resetting a variable 
alive and in use in another which is of course, the basis for most 
objections to Global variables.  I never did finally determine the exact 
cause of the wayward database objects as I saw the advantage of 
circumventing the issue sooner than I could determine the cause.

Hen


>From: Gustav Brock <gustav at cactus.dk>
>Reply-To: Access Developers discussion and problem 
>solving<accessd at databaseadvisors.com>
>To: Access Developers discussion and problem 
>solving<accessd at databaseadvisors.com>
>Subject: Re: Betreft: RE: [AccessD] ..Performance ADO - DAO ..
>Date: Tue, 21 Oct 2003 19:27:48 +0200
>
>Hi Marty
>
> > You don't have to worry about anything at all. You will initialize
> > the global variable only when you need to, and the reference
> > returned will always be guaranteed to be accurate.
>
>Except when you make changes to, say, the TableDefs collection ...
>
>Using DBEngine(0)(0) all you need is a Refresh but with a static
>dbCurrent you'll get toasted.
>
>/gustav

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