Re: Possible bridges between OO programming proponents and relational model
Date: 3 Jun 2006 04:46:37 -0700
Thank you for your feedback. I do not believe I am making any confusion but I should rephrase otherwise for the sake of clarity. (Again English is not my native language so expressing consensual terminology in english is difficult to me. As Fabian PASCAL declared "commitment" to precise terminology is crucial into abording relational model matters).
First, I make a clear distinction between SQL and its current proprietary implementations(DB2, ORACLE, SQL Server...). As you know, several features specified in standard (SQL92) have not been implemented, creating lots of overhead work at applicative level into guaranteing integrity at physical implementation time (ex:create table) which makes SQL implementations and therefore SQL DBMS's unefficient. Of course, there is no better alternative as SQL based systems are still the best we have.
Second, I make a clear distinction between SQL tables *as implemented currently* and relvars (called also R-tables). On that standpoint, I do not see how are current *physical* implementations of SQL are multidimensional when all the ones I know (but I only know the main exposed above) use direct image storage of tuple physical implementation.(totally defeating relational independence between logical and physical layer). So I am curious to why, presicely you are saying that a SQL table is multidimensional. My guess is that you are refering to what SQL should be as opposed as to how it is implemented. On that case, I agree with that statement. On the opposite case
Third, the hidden agenda of this thread is to focus discussion on in-memory logic projection of relvars assuming total independence between disk based storage and representation of R-Tables at runtime. As you also know current SQL implementations (and SQL implemented tables) are direct projection of physically static (generally bidimensional) representation of tuples. On such perspective, the little education I have about OO mechanisms encourages me to seek discussion with OO audience to educate myself about possibilities OO can offer to drive a better relational implementation.
So no. I do not believe what I am writing is nonsense. So I will stick to what I have declared previously. Do not hesitate to contradict me if you believe I missed some points. Thank you for your implication in this thread.
Bob Badour wrote:
> Cimode wrote:
> > One of the main current flaws of current SQL DBMS systems is their
> > incapability to implement the multidimensionality of relvars.
> With all due respect, what you wrote is nonsense. An SQL table of degree
> N (ie. with N columns) has N dimensions.
Received on Sat Jun 03 2006 - 13:46:37 CEST