Re: If you were to implement the original relation algebra language...

"Bob Badour" <[EMAIL PROTECTED]> wrote in message <news:[EMAIL PROTECTED]>...

> "Marshall Spight" <[EMAIL PROTECTED]> wrote in message
> news:[EMAIL PROTECTED]
> > "Paul Vernon" <[EMAIL PROTECTED]> wrote in message
> news:[EMAIL PROTECTED]
> > >
> > > I guess we would be better off moving away from infix operators and
> using
> > > prefix/functional operations instead in relational algebra grammers.
> >
> > I think we would be better off providing the language with enough
> > flexibility so that the programmer can choose the most appropriate
> > form of expression at the time. cf. Haskell.
>
> Are you suggesting you prefer redundant languages?

One might have to, to get the camel's nose into the tent.
Even though relational algebra is no less powerful than
relational calculus, some queries may be easier to express
in relational calculus.  Use Codd's reduction algorithm to
translate it to the relational algebra.  Next up, the SQL
mutants used in ODBC and JDBC unless you want shelfware...

If the parser and optimizer for the One True Relational
Algebra are smart enough, the translators for the Great
Unwashed can get away with being dumber and less work to
implement.  Some syntactic sugar may have to creep into
the One True language, otherwise a translator would need
information about R1's value to convert a sugar-frosted
R1 { ALL BUT ATTRIBUTE1 } to R1 { ATTRIBUTE2, ATTRIBUTE3,
ATTRIBUTEX, ATTRIBUTEY, ATTRIBUTEZ, ... } let alone what
would be needed to convert any JOIN to a product, rename,
restrict, and sugar-free project.

--
Joe Foster <mailto:jlfoster%40znet.com>  "Regged" again? <http://www.xenu.net/>
WARNING: I cannot be held responsible for the above        They're   coming  to
because  my cats have  apparently  learned to type.        take me away, ha ha!