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Re: No exceptions?

From: paul c <toledobythesea_at_oohay.ac>
Date: Fri, 30 Jun 2006 22:12:39 GMT
Message-ID: <rlhpg.111313$Mn5.39829@pd7tw3no>


Jon Heggland wrote:
> paul c wrote:

>> Let me re-phrase my original question:  Is there a logical flaw in
>> substituting TABLE_DUM for x in the expression "x join y" when x is not
>> in the catalogue?
>>

>
> I don't know what precisely you mean by "logical flaw", so I'll pass
> judgement. If something should be substituted for x (a "default value",
> so to speak), TABLE_DUM does seem the natural choice, though, as it
> corresponds to false/zero in some sense.
>
>> (Assuming that the syntax requires x to be a relation and with the whole
>> expression's value being TABLE_DUM as well and granting that such a
>> result might seem surprising to most people.)

>
> "TABLE_DUM join y" evaluates to the empty relation with y's heading, not
> TABLE_DUM (unless y's header is also empty, of course).

Right, sorry about that.

p Received on Fri Jun 30 2006 - 17:12:39 CDT

Original text of this message

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