Re: A better SQL implementation?

From: David Portas <>
Date: 8 Jun 2006 09:58:02 -0700
Message-ID: <>

Cimode wrote:

> What prevents using '=' as an operator to
> mean 'CONTAINS' concept.

Common sense. Why give the same operator two different (and potentially contradictory) meanings? In this case you can't even determine the meaning from the rest of the context so it's doubly bad and doubly dangerous.

> If you believe SQL has a sufficient support of complex data types such
> as Document (set of words), what are the operators would define this
> particular data type then using traditional SQL? (thank you for
> adressing this particular definition.)


WHERE document LIKE '%foo%' AND document LIKE '%bar%'

> But I also believe the argumentation developped by the paper
> exclusively concerns physical implementation even if he is not using
> the right terminology. Index are implementation level and problems
> expressed are real. I have encountered them countless times with
> traditional SQL.

The argument *should* be one of physical implementation. But the paper says nothing useful about it! It presents no new implementation features at all. Most of the paper is taken up with discussion of queries, which have nothing to do with implementation.

> I am curious as to why you believe that the logical meaning of '=' is
> redefined by the author. He just uses the operator to define a
> specific data type...

If the author was using the usual logical meaning for = then the expression:

kw = 'kw1' and kw = 'kw2'

could not evaluate to anything other than FALSE (or UNKNOWN in 3VL). That's not the result implied by the paper. Maybe he means we are to interpret his queries differently somehow. Since he explains nothing we have to guess everything.

> Let's give him a chance...

I don't think he's said anything that has a chance really.

David Portas
Received on Thu Jun 08 2006 - 18:58:02 CEST

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