[AccessD] Recording field changes

Hi Stuart:

In this case you are not saving two hundred fields, only the fields with
changes are stored. Access MDB uses variable length fields not fixed
length...no data no length.

Also please note that I did say ...'or at least any field that a user can
affect.'

As the tables become larger with more individual records the slower the
speed; so if a user makes, say, fifty changes to a large record, there is a
potential for fifty individual records being created in the transaction
file. Now that could add-up very rapidly and the overhead would finally
degrade performance.

My recommendation is that for each separate change/session, only one
transaction record is created for any and all changes to any fields of that
record and only the changes are stored. Like an incremental backup/change
log and incremental backups are always fastest. Handling this type of system
may be simpler using an unbound format but it should be as simple as
comparing the differences between the field's 'text' and 'value' properties
in bound format.

HTH
Jim

-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com]On Behalf Of Stuart
McLachlan
Sent: Monday, June 21, 2004 2:57 PM
To: Access Developers discussion and problem solving
Subject: RE: [AccessD] Recording field changes


On 21 Jun 2004 at 14:28, Jim Lawrence (AccessD) wrote:

> David:
>
> If the client wants to see all changes to a record on a field by field
bases
> then the/each transaction file(s) will have to have a minimum of a
complete
> copy of each record structure of each table or at least any field that a
> user can affect.

Not necessarily.  I've fallen into that trap before. Why save 200 fields
when
only 1 changed.  For many environments, it's quite sufficient to  just
store:
"FieldName,OldValue,TimeStamp,Operator".



--
Lexacorp Ltd
http://www.lexacorp.com.pg
Information Technology Consultancy, Software Development,System Support.



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