Re: What databases have taught me

Bob Badour wrote:
Marshall wrote:

Bob Badour wrote:

Would (R AND x = 1 AND y = 2) = (x = 1 AND y = 2 AND R) ?

I'd think it would have to, wouldn't it? Assuming = binds with
higher precedence than AND in the above syntax, and assuming
AND is associative and commutative, which I would hope it
would be. It is in the Tropashko algebra.


If so, wouldn't that make name resolution kinda complicated and perhaps
error-prone?

I don't see any obvious complications to name resolution, but then
I might be mising what you're getting at.

How will the dbms know when a name refers to an attribute vs a relation
variable?

Consider:

R AND x = y

What if the dbms has relvars x and y and R has attributes x and y?

Ah, I see what you're saying now. Yes, that could well be an issue.
I'm not familiar enough with this syntax to say much.


As to error-prone,
(assuming we are talking about the progammer writing the
above code) yes, it might be, especially at first. I would
expect to address that issue with coding conventions and
possibly syntactic support. It's hard to say how much of
an issue that will be without field experiece. (Which I don't
have with this question.)

Okay, as long as we are not talking about the language the programmer
works in, one can handle name resolution syntactically in the
human-readable language and use something unambiguous internally.

Yes. Again, I'm not much familiar with the above syntax, but I could
well imagine some challenges cropping up, given the lack of any
marker characters and the (multiple?) uses of '='.


Marshall

.

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