Mailing List Archive: 49091 messages
  • Home
  • Script library
  • AltME Archive
  • Mailing list
  • Articles Index
  • Site search

[REBOL] [DEV] Re: dbms3.r 01

From: g:santilli:tiscalinet:it at: 13-Jan-2002 19:57

Hello Joel! On 13-Gen-02, you wrote: JN> At the same time, it takes real courage to expose one's JN> thinking in near-real-time to an audience or a group of JN> collaborators. I applaud your bravery! Well, I hope you will all be indulgent to me. :) JN> My experience suggests that there's value in three kinds of JN> access to elements of a collection, which I'll call by JN> semi-arbitrary names for this discussion: JN> 1) "physical" access -- corresponding to your notion of JN> "row-ID" JN> in which traversal of a collection is done in the fastest JN> possible manner -- SINGLE VALUED. This is the case for the low-level functions. JN> 2) "identity" access -- via a unique ID which is guaranteed JN> not to change throughout the lifetime of the collection JN> (a JN> sort of "true name" of each entity) allowing references JN> to JN> entities in the collection to remain valid even if the JN> order JN> or structure changes -- SINGLE VALUED. This is why I used them in dbms.r; but now I'd like to abstract more and let the user decide the keys for a table. Anyway, as things proceed, I might decide to include some kind of special key to optimize speed. JN> 3) "criteria-based" access -- via a search expression, which JN> may refer to one or more attributes of an entity, JN> possibly JN> represented as a function passed to an iterator which JN> finds JN> and presents all entities possessing the specified JN> property(ies) JN> -- SINGLE OR MULTIPLE VALUED. This is what the user sees, even in the current dbms.r. JN> I'd suggest that "row-ID" be as thoroughly hidden as JN> possible, e.g., only used within a loop that is scanning the The plan is that it will be used in indices only, internally. If a row gets moved for some reason, the index can be updated; of course I think such change will not be very frequent, but mainly originating from an optimization of the table or something like that... JN> Just my $0.015 of the moment ;-) Thanks! They are much appreciated. :) Regards, Gabriele. -- Gabriele Santilli <[giesse--writeme--com]> - Amigan - REBOL programmer Amiga Group Italia sez. L'Aquila --