Simple Dataset Question

[Rich Wallace]

I know datasets have been beaten to death in here, I have what is hopefully
a simple question about the integrity of a dataset when used in an
application.

Scenario:
User A and User B are updating data in a SQL database via an application
that utilizes a dataset, dataadapter and datagrid.

User A retrieves data from data source and sits on the data for some time
User B retrieves SAME data from source, changes data via teh datagrid and
updates the data source using the dataadpter
User A makes changes to the data using the datagrid and then attempts to
update the data source

How smart is the dataset/dataadapter to know that the data was changed by
User B since the last time User A retrieved the data? Will User B's changes
be overwritten by User A's changes?

If so, how does one prevent this or how can the developer notify User A that
the data is no longer accurate based on what they saw in the datagrid?

TIA!
-Rich

 

[Guest]

The dataset/dataadapter in User A will never know that the data was changed by User B because dataset/dataadapter just get a snapshot like a client side cursor. Whether overwrite data changed by User B or refuse data changed by User A depends on how you implement in dataadapter.updatecommand

 

[Cor Ligthert]

Hi Rich,

That is why it is called optimistic concurrency, when this is happening you
have to trap that in the dataadapter update. Have a look for that on MSDN.

Some links to start.

http://msdn.microsoft.com/library/d.../vbcon/html/vbtskcatchingconcurrencyerror.asp

http://msdn.microsoft.com/library/d...s/cpguide/html/cpconOptimisticConcurrency.asp

I hope this helps?

Cor