[AccessD] Missing records

Okay, what does DIY mean?
T

Charlotte Foust wrote:

>I have to agree with you, Gustav.  Cascading deletes are definitely not
>for DIY users but properly implemented, they save a lot of code!
>
>Charlotte Foust
>
>
>-----Original Message-----
>From: accessd-bounces at databaseadvisors.com
>[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Gustav Brock
>Sent: Friday, February 03, 2006 8:01 AM
>To: accessd at databaseadvisors.com
>Subject: Re: [AccessD] Missing records
>
>
>Hi John
>
>Oh no, why are you beating this horse again?
>
>Cascade delete is a very powerful and useful feature.
>However - just like fire - implement it only when you know what you are
>doing.
>
>Your example with invoices is bad. You never delete an invoice, and if
>you do (it might be a draft only) you will wish to delete all its
>invoice lines too. If you don't, you will have orphaned invoice lines,
>or you will have to bother the user with deleting line by line until the
>draft is empty and can be deleted.
>
>You may program your own routines to be fired at a click of the
>supervisor's button, but doing so is somewhat similar to building
>unbound forms in Access.
>
>As I wrote last time: You know all about this - normalization, relations
>and so on - so why be so scared?
>
>/gustav
>
>  
>
>>>>jwcolby at ColbyConsulting.com 03-02-2006 16:33:46 >>>
>>>>        
>>>>
>John,
>
>The first thing to do is examine the relationships for the tables
>missing records.  If "cascade delete" is turned on (a NO-NO in my humble
>opinion) then deleting a single record (such as a customer) will (after
>a warning of
>course) delete ALL child/grandchild/...greatgreatgreat records.  
>
>Let's say that a client has invoices and invoice line items.  Yep, all
>gone. Repair service calls / line items?  Yep, all gone.  Payments?
>Yep, all gone.
>
>Cascade delete of a single (for example) customer record WILL delete all
>child records, however far down they go.  Potentially dozens or even
>thousands of records, all gone because the user was "just deleting a
>single customer record".
>
>I pretty much design my databases to never turn on Cascade delete, and
>then build delete queries tied to buttons which only supervisors can
>see/click.
>
>John W. Colby
>www.ColbyConsulting.com 
>
>  
>