Yes, leave it in the database and get it when required.

I would certainly not store large volumes of data in a dataset - techncially
they should be transiant, holding data currently being worked on - or
pointers to the data in the database for drill-down, and of course if you
hold it there all day it could likely become invalidated as the status of
orders change. That however is a design issue, but you should be looking at
making use of things like cache invalidation against selected data and
working on some traffic management and making correct use of the database
this data sits within.

You could store a subset, or the whole dataset as a local XML file,
depending on what your client is.  Net has advanced classes for handling
XML - that way its local but not resident in memory.

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Regards

John Timney (MVP)