Re: What should be the Database Design in this case?

>> Joe, I respectfully disagree. The relational model says nothing
about how,
where or how often one stores anything. Storage is physical. Even creating an index generally increases redundant storage. <<

>> Whether one creates a view or a snapshot, the logical
representation has exactly the same redundancy. <<

Snapshots are frozen at a moment in time and are base tables. Views are built each time they are invoked and can change during a session, depending on your transaction level. Big logical and practical differences!

If I build a base table to hold summary data, it is logically redundant because it can be calculated from the details that were summaried. If I create A VIEW (i.e. a virtual table taking up no storage when not in use), then the summary is always right at the time of invocation. To guarantee that a base table, would always be current, I would need a constraint and some kind of action (i.e. triggers or stored procedure) that was guuaranteed to be applied each and every time a detail was changed. Received on Mon Dec 09 2002 - 18:36:44 CET