[dba-VB] Merge / Purge

Unless they have data in the same fields.  Then what happens?

Charlotte Foust 

-----Original Message-----
From: dba-vb-bounces at databaseadvisors.com
[mailto:dba-vb-bounces at databaseadvisors.com] On Behalf Of jwcolby
Sent: Wednesday, October 14, 2009 1:20 PM
To: stuart at lexacorp.com.pg; Discussion concerning Visual Basic and
related programming issues.
Subject: Re: [dba-VB] Merge / Purge

Stuart,

Yes there is a PKID.  The thing is, every record is equal so it simply
doesn't matter in which order the records are pulled.  Any of the
duplicates can be treated as the first record to be updated by whatever
is found in the subsequent records.

It literally doesn't matter which record is encountered first.

John W. Colby
www.ColbyConsulting.com


Stuart McLachlan wrote:
> John,
> 
>>>> wins" strategy. Every field in every record has to be examined. 
>>>> "Existing data" cannot
> be
>>>> overwritten by "no data" but MUST be overwritten by "most recent 
>>>> data". Recent is
> defined by record
>>>> position, NOT date (I don't have date info).
> 
> SQL Server doesn't have a concept of chronological record position. 
> Unless there is atimestamp or incrementing field, there is no way to 
> know which is the most recent entry or to guarantee that the most
recent will be the "last" record in the recordset selected.
> 
> Do use have an incrementing key field?
> 
> 
> Stuart McLachlan
> 
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