[AccessD] Unbound Again

Martin Reid mwp.reid at qub.ac.uk
Fri Dec 22 11:08:14 CST 2006


I am thinking that locking is the key to working unbound. All the other stuff is nice and easy really. Add, Edit, Delete etc is very much standard stuff. Its the locking that will catch many people out. Maybe I should write up a bit on that for this section.
 
Martin
 
Martin WP Reid
Training and Assessment Unit
Riddle Hall
Belfast
 
tel: 02890 974477
 

________________________________

From: accessd-bounces at databaseadvisors.com on behalf of Jim Lawrence
Sent: Fri 22/12/2006 16:48
To: 'Access Developers discussion and problem solving'
Subject: Re: [AccessD] Unbound Again



Hi Martin:

John is right about the locking issues. Until recently when trying to lock a
specific record in Access the DAO database would lock a group of records.

The way to handle that is to:

All tables should have a timestamp, locked and user code field.

When a record's contents are pulled into a (disconnected) recordset, the
records' timestamp and user code field is immediately updated and the lock
field is set.

After the editing process is completed the table record is updated and the
lock field is cleared.

This is very similar to the way both MS SQL and Oracle manage their tables.

HTH
Jim    

-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of JWColby
Sent: Friday, December 22, 2006 6:45 AM
To: 'Access Developers discussion and problem solving'
Subject: Re: [AccessD] Unbound Again

Martin,

One problem with unbound is the whole locking issue, which the bound method
handles for you.  Unless you place a lock on the record you are editing,
then how do you know that the underlying record wasn't updated by another
user while this user was eating lunch?  Thus for simple unbound, probably
only updating fields changed is the safest.  If your form is going to lock
the record being edited, then you can safely update the entire record.  Or
you could refetch the original, compare the field values of the original to
the "old values" of the unbound form, and warn the user if there were
changes to the original.  Many different answers to that seemingly simple
question.


John W. Colby
Colby Consulting
www.ColbyConsulting.com

-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Martin Reid
Sent: Friday, December 22, 2006 8:10 AM
To: Access Developers discussion and problem solving
Subject: [AccessD] Unbound Again

Back to the unbound edit

So the idea I am using is to

1. Click The Edit Button
2. Unlock fields
2. Change edit caption to save

So the suer changes one field. Do you just simply update the whole record ot
do you test each field and only chane the one edited? Or is there any issue
with either?

Martin

Martin WP Reid
Training and Assessment Unit
Riddle Hall
Belfast

tel: 02890 974477



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