🚀 go-pugleaf

> >Make sure you have CachedUpdates = true, and in the AfterPost event do
> >ApplyUpdates() and CommitUpdates().
>
> This is a bit unclear.  From the help files, I gather that
> ApplyUpdates() writes the cache out to somewhere, and CommitUpdates()
> is misnamed, and only clears the cache.

Keep in mind that CommitUpdates will actually retry any updates that fail or
were skipped. I never realized this until I actually saw it in action. This
may be ok for some people, but my updates are rely heavily on transactions.
I can't have updates happening behind my back that are outside of
transaction control.

For this reason, I actually call CanceUpdates to clear the cache, even for
successful updates. It's faster, and I don't get the retries. Plus, in my
code I always to a requery after an update anyway. I think if I used
CommitUpdates, I might not have to do a requery (I don't remember).


> So if I make some changes, call ApplyUpdates(), then CommitUpdates(),
> then makes some changes, repeat the ApplyUpdates() and
> CommitUpdates(), *then* call the Database->Commit(), will the first
> changes get commited to the database?

I believe so.

> Also, if I want to cancel the changes to just one TQuery resultset, do
> I need to call TQuery::Cancel(), TQuery::CommitUpdates(), or both, or
> something else?

Cancel only makes sense when a dataset is in insert or edit mode. The cancel
operation takes the dataset back to browse mode, and aborts changes to that
one record. If this is what you want, use Cancel. If you want to completely
wipe all pending changes to all records in a datatset, call CancelUpdates.
CommitUpdates may actually do something you don't want.

PS: CommitUpdates and CancelUpdates only make sense in datasets that use
CachedUpdates. Cancel is a routine that you can always use.

> In the help files, the example shows to ApplyUpdates(), then call the
> database Commit(), then CommitUpdates().  Is that sequence actually
> required?

It's not the required sequence, but I think it is the sequence that makes
the most sense.

--
Harold Howe [TeamB]
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Custom software development:  http://www.bcbdev.com/resume.htm