Re: Smart Database Tricks

From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Fri, 22 Jun 2007 09:25:25 -0300
Message-ID: <467bbfa9$0$4321$9a566e8b@news.aliant.net>

Jan Hidders wrote:

> On 22 jun, 01:36, Bob Badour <bbad..._at_pei.sympatico.ca> wrote:
> 

>>Jan Hidders wrote:
>>
>>>On 21 jun, 21:17, vldm10 <vld..._at_yahoo.com> wrote:
>>
>>>>On Jun 18, 7:41 pm, Jan Hidders <hidd..._at_gmail.com> wrote:
>>
>>>>>On 18 jun, 20:59, vldm10 <vld..._at_yahoo.com> wrote:
>>
>>[snip]
>>
>>
>>>>>If this is a relation then
>>>>>all columns are attributes and since you have represented all the
>>
>>>>Can you please, tell me what is the definition of the attribute in RM.
>>
>>>It's a column of a relation. Conceptually it represent the role in the
>>>predicate that is represented by the relation.
>>
>>Is an attribute a predicate variable of some sort?

> 
> As in "the x in predicate P(x, y) "? Yes, I'd say that is the same
> thing.

I thought so. When one writes a query and requests certain attributes, would those requested attributes be free variables in a logic sense?

When one uses an attribute in a restrict condition or join condition, would that attribute be a bound variable in a logic sense? Received on Fri Jun 22 2007 - 07:25:25 CDT