Re: creating database

[Jacob Sparre Andersen <sparre@nbi.dk>]

Ludovic Brenta writes:

> Your question is not specific to Ada or any particular language.  It
> is a design question.  If I understand well, you're trying to store
> a variable (and unknown at compile time) number of "things" in
> memory.  There are many well-known data structures to choose from,
> or you could roll your own.  The simplest data structure you can try
> is called a "linked list".  Look it up on Google.  A linked list is
> simple and efficient when adding new "things", but inefficient when
> searching for one particular "thing".  Most industrial-strength
> database engines use more sophisticated data structures such as
> B-trees (q.v., on Google).

And some of these types of data-structures exist as a part of the
standard library in the upcoming revision of the Ada standard.  If you
want to take a look at the current version of this extension of the
standard library, "AI302" and "Ada.Containers" are the keywords to
search for.

In one of the most recent Ada journals (I can't remember if it was the
ACM or the Ada Europe one), there was an overview of the trade-offs
related to selecting different kinds of containers.  That's probably a
good reference for anybody choosing which variant of "Ada.Containers"
to use.

Jacob
-- 
�By becoming continuous, war has fundamentally changed its character.
 In past ages, a war, almost by definition, was something that sooner
 or later came to an end, usually in unmistakable victory or defeat.�
                               -- Nineteen Eighty-Four, George Orwell
�I don't think you can win [the war on terror].�    -- George W. Bush