DIFFERENTIAL backup

Just want to clarify the date from which a DB backup with DIFFERENTIAL
option includes its changes.
I have a db which I do a full backup on Saturday, and a differential the
other days (this is plenty in our case)
If someone performs an ad-hoc backup for whatever reason during the
week, say prior to a roll-out, I assume the DIFFERENTIAL backup that
night will only include changes back to the ad-hoc backup? Can I force
it to go back to the Saturday one at all?> If someone performs an ad-hoc backup for whatever reason during the week, say prior to a roll-out,
> I assume the DIFFERENTIAL backup that night will only include changes back to the ad-hoc backup?
Yes, assuming that the ad-hoc backup was a full database backup.
> Can I force it to go back to the Saturday one at all?
No. However the ad-hoc backup should have been taken using the COPY_ONLY clause (new in 2005). That
will not break the backup sequence for diff backups.
--
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://sqlblog.com/blogs/tibor_karaszi
"Ben Rum" <bmwbase-newsgroup@.yahoo.com> wrote in message news:eul5oi$h51$1@.news-02.connect.com.au...
> Just want to clarify the date from which a DB backup with DIFFERENTIAL option includes its
> changes.
> I have a db which I do a full backup on Saturday, and a differential the other days (this is
> plenty in our case)
> If someone performs an ad-hoc backup for whatever reason during the week, say prior to a roll-out,
> I assume the DIFFERENTIAL backup that night will only include changes back to the ad-hoc backup?
> Can I force it to go back to the Saturday one at all?