Re: merge on datasets from join queries

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From: Glenn (g.e.r_at_comcast.net)
Date: 09/27/04 

Date: Mon, 27 Sep 2004 08:39:31 -0500

Sahil:

The source and destination datasets are being filled by the same stored
procedure and have the same
table name. Your comment that "Dataadapter.fill, will not by default pull
in primary key
 information etc" pointed me in a helpful direction: the query is an outer
join and Help said that you need to add a primary key for outer joins (they
are not pulled in)

This helped somewhat, now changes made by others are reflected and rows
added by others are added, but for some reason rows not in the source
dataset (either deleted by others or modifired so they do not meet the
criteria of the original dataset) are not removed from the destination
dataset.

My scenario is that a user has a list of items, usually filtered by a
status, from which he picks a record to load and edit. This list is
refreshed periodically to reflect changes by other users. If another user
has edited a displayed record so that it no longer meets the filter for the
list, when the refresh is run and the record is no longer in the source
dataset, I want it removed from the list. This is not happening on the
merge.

I guess I have to loop through and handle manually.

Thanks for your help.

Glenn

"Sahil Malik" <contactmethrumyblog@nospam.com> wrote in message
news:u5edkC$oEHA.3424@TK2MSFTNGP12.phx.gbl...
> Glenn,
>
> If I understood correctly, Problem statement - "You want to refresh the
> contents of your dataset with changes happening in the database".
>
> I believe you are on the right track for the solution. Consider the
> following --
>
> a) Join queries are in the database, Dataset.Merge is in ADO.NET -- Two
> different animals. We can simplify this situation by, "You are filling the
> dataset somehow".
> b) Have you specified a primary key on the two Datatables (in ADO.NET) you
> are trying to merge within your datasets? More so, are the Datatable names
> the same? Dataadapter.fill, will not by default pull in primary key
> information etc. There is a fillschema, method but my recommendation is
not
> to use that in a production application since that executes a fairly heavy
> query on your d/b.
>
> Dataset.Merge has pretty clearly laid out rules of how it will merge. And
> yes it can be used to refresh data from the database (or anywhere else).
>
> - Sahil Malik
> You can reach me thru my blog -
> http://www.dotnetjunkies.com/weblog/sahilmalik
>
>
>
> "Glenn" <g.e.r@comcast.net> wrote in message
> news:Oa36xl8oEHA.1988@TK2MSFTNGP09.phx.gbl...
> >I have lookup/record selection grids bound to datasets with lists based
on
> > join queries. Periodically, I want to update these datasets to reflect
> > changes made by other users. It seems the dataset.merge on the original
> > dataset with a dataset of the refreshed records just duplicates the
> > records.
> > Although the list is a main table with PK and the other tables in the
join
> > query are just lookup values (leaving only one record per PK), the
dataset
> > merge does not work.
> >
> > Is this possible or is the only way to "refresh" a dataset based on a
> > joined
> > table to loop through and update each field? Note, I do not want to
just
> > re-fill the original dataset as it is bound to a grid and so all the
event
> > firing and other binding operations would be more difficult to handle.
> >
> > Thanks.
> >
> > Glenn
> >
> >
>
>

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