Re: Windows Ada database support.

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Mon, 29 Nov 2004 16:02:44 +0100, Frank Piron wrote:

> Fri, 26 Nov 2004 10:15:06 +0100 Dmitry A. Kazakov 
> <mailbox@dmitry-kazakov.de> wrote:
> 
>> And more importantly why that crappy SQL over and over again? I would 
>> like
>> to see a high level Ada.Database[.Relational?] package totally 
>> independent
>> on what happens beneath.
>>
> But what language for querying and manipulating data would you
> suggest?
> IMO it should
> 
> - be declarative
> - boolean closed
> - allow restricted quantification

Yes.

> Some LQL (Logical query language based on Predicate Calculus)
> would be nice.
> Example: (Database for Genealogical data)
> 
> Base Predicates(Tables): Person(x,s), Parent(x,y)     |(s = sex)
> Show all Fathers:
> 
> LQL:
> Father(x):=E(y)[Person(x,s) and
>                  s='MALE'    and
>                  Parent(x,y)
>                  ]
> 
> SQL:
> select Person.x
>       from Person, Parent
>        where Person.s='MALE' and
>              Person.x = Parent.x   (inner join for the E-Quantifier)
> 
> Similar to Prolog.
> 
> Other implementations would use only persistent types and their methods
> in a distributed environment (like Cach�).

Ideally it should be a direct use of Ada's ADT. It should be true ADT, not
just a data representation, also stored procedures (are they Turing
complete, BTW? (:-)) I don't know how realistic it will be in 2010, but
sooner or later a new generation of OO data bases will support ADT.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de