Re: VIEWS compared to Nodes as Windows into data
Date: 29 Apr 2004 17:52:40 GMT
Centuries ago, Nostradamus foresaw when "Dawn M. Wolthuis" <dwolt_at_tincat-group.com> would write:
> "Dawn M. Wolthuis" <dwolt_at_tincat-group.com> wrote in message
>> Given a database application implemented in an RDBMS with 632 tables where
>> we want to give Pat an online data catalog from which to shop for data
>> values by way of metadata, we would likely provide a set of SQL VIEWS,
>> From what I have seen, if there is data in a supporting table XYZ that is
>> only sometimes needed when reporting about a particular entity (such as
>> Customers), then one might have two VIEWS of that data -- one with and one
>> without XYZ joined in.
> Is this an accurate perspective on SQL VIEWS? Are there "extra" VIEWS, more
> portals into the data, or whatever, created simply for performance reasons?
> Is there a DBMS that provides a better top level "data catalog" that doesn't
> include performance issues mixed with what data values you can "shop for"
VIEWS are created for all sorts of reasons, typically:
- To provide convenient perspectives on data;
- To structure the data better from a security perspective.
They aren't created for "performance" reasons; if anything, they are likely to cut performance slightly. Their point is either to provide better abstraction or to to hide details.
-- (reverse (concatenate 'string "moc.enworbbc" "_at_" "enworbbc")) http://cbbrowne.com/info/spreadsheets.html Rules of the Evil Overlord #194. "I will make several ludicrously erroneous maps to secret passages in my fortress and hire travellers to entrust them to aged hermits." <http://www.eviloverlord.com/>Received on Thu Apr 29 2004 - 19:52:40 CEST