ajs@prg.ox.ac.uk (Adolfo Socorro) (02/04/91)
In article <SCHULTZ.91Feb2120216@halley.est.3m.com> John Schultz writes:
While embedding OODB calls in an
existing language would be ``seamless'' ...
I have to wholeheartedly disagree. If one is forced to be bilingual, and to
back and forth map data structures between computational systems, then the
integration can't be seamless. The field of database programming languages
tries to address this question; that is, to develop the technology that avoids
the so-called impedance mismatch that results when two languages are merged in
an ad-hoc fashion, with particular attention to database issues.
--Adolfoballou@databs.enet.dec.com (02/06/91)
In article <1194@culhua.prg.ox.ac.uk>, ajs@prg.ox.ac.uk (Adolfo Socorro) writes: |> In article <SCHULTZ.91Feb2120216@halley.est.3m.com> John Schultz writes: |> |> While embedding OODB calls in an |> existing language would be ``seamless'' ... |> |> I have to wholeheartedly disagree. If one is forced to be bilingual, and to |> back and forth map data structures between computational systems, then the |> integration can't be seamless. The field of database programming languages |> tries to address this question; that is, to develop the technology that avoids |> the so-called impedance mismatch that results when two languages are merged in |> an ad-hoc fashion, with particular attention to database issues. ...and less attention to programming language features. I think you missed the real question. Rephrased: Do computationally different models strictly require different languages? Nat P.S. - most use 'impedance mismatch' as a complaint with the current rash of database programming languages (i.e., SQL, QUEL, etc.).
sakkinen@tukki.jyu.fi (Markku Sakkinen) (02/07/91)
In article <1991Feb6.091642@databs.enet.dec.com> ballou@databs.enet.dec.com () writes: >In article <1194@culhua.prg.ox.ac.uk>, ajs@prg.ox.ac.uk (Adolfo Socorro) >writes: >|> In article <SCHULTZ.91Feb2120216@halley.est.3m.com> John Schultz writes: >|> >|> While embedding OODB calls in an >|> existing language would be ``seamless'' ... >|> >|> I have to wholeheartedly disagree. If one is forced to be bilingual, and to >|> back and forth map data structures between computational systems, then the >|> integration can't be seamless. The field of database programming languages >|> tries to address this question; that is, to develop the technology that >avoids >|> the so-called impedance mismatch that results when two languages are merged >in >|> an ad-hoc fashion, with particular attention to database issues. > >...and less attention to programming language features. I think you missed the >real question. > >Rephrased: Do computationally different models strictly require different > languages? > >Nat > >P.S. - most use 'impedance mismatch' as a complaint with the current rash > of database programming languages (i.e., SQL, QUEL, etc.). Now here is a very understandable little confusion. Those languages you mention are database _query_ languages (remember where the 'Q' in the acronyms comes from), although they can be used for updates and other things that are not "queries" in the older and stricter sense. Sales pitches usually speak of "fourth-generation languages" (4GL). The people who advocate database _programming_ languages dislike the incomplete computational power (and often quite "ad hoc" features) of these query languages, which therefore must usually be combined (embedded) in a more or less awkward way with some conventional programming language when nontrivial applications are built. Absolutely recommended reading: "Types and Persistence in Database Programming Languages" by M.P. Atkinson and O.P. Buneman, ACM Computing Surveys, June 1987 (actually appeared in Spring 1988). Markku Sakkinen Department of Computer Science and Information Systems University of Jyvaskyla (a's with umlauts) PL 35 SF-40351 Jyvaskyla (umlauts again) Finland SAKKINEN@FINJYU.bitnet (alternative network address)