Re: VAT rate or VAT amount as a column?
From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Sun, 06 Aug 2006 13:26:53 GMT
Message-ID: <x6mBg.35726$pu3.465238_at_ursa-nb00s0.nbnet.nb.ca>
>>Emily Jones wrote:
>>
>>>A view isn't the same as a base table though is it? Materialised or not.
>>
>>No, a view, by definition, is not a base table. The base tables provide
>>the raw (logical) material from which we construct application views.
>>While each application might view the database as a normalized set of
>>relations, the union of the application views and the base tables
>>generally won't be normalized and will have considerable redundancy.
>>
>>While views are derived from the base tables, though, the base tables
>>are themselves derived from physical storage. Thus it is conceivable
>>that an attribute in a base table will be derived from other stored
>>attributes rather than physically stored itself. That's generally not
>>possible with available SQL dbmses at this time.
Date: Sun, 06 Aug 2006 13:26:53 GMT
Message-ID: <x6mBg.35726$pu3.465238_at_ursa-nb00s0.nbnet.nb.ca>
> "Bob Badour" <bbadour_at_pei.sympatico.ca> wrote in message > news:aVlBg.35723$pu3.465389_at_ursa-nb00s0.nbnet.nb.ca... >
>>Emily Jones wrote:
>>
>>>A view isn't the same as a base table though is it? Materialised or not.
>>
>>No, a view, by definition, is not a base table. The base tables provide
>>the raw (logical) material from which we construct application views.
>>While each application might view the database as a normalized set of
>>relations, the union of the application views and the base tables
>>generally won't be normalized and will have considerable redundancy.
>>
>>While views are derived from the base tables, though, the base tables
>>are themselves derived from physical storage. Thus it is conceivable
>>that an attribute in a base table will be derived from other stored
>>attributes rather than physically stored itself. That's generally not
>>possible with available SQL dbmses at this time.
> > I'm not sure I understand the above. > > Interbase has a feature called a "computed by" column. Such a column is not > stored, but is materialied on demand. > Is this an example of what you are talking about?
It could be. I am not familiar enough with Interbase to say with any confidence. Received on Sun Aug 06 2006 - 15:26:53 CEST