Re: relational tables and objects
From: Jonathan Leffler <jleffler_at_earthlink.net>
Date: Sun, 03 Nov 2002 05:16:11 GMT
Message-ID: <3DC4B0C5.9080407_at_earthlink.net>
>
> Sure. RTL checks if a relational operation is valid in compile-time. All
> checks and schema computations are done in comile-time. In compile
> time we calculate list of colums of result, sort order, check if
> colums, on which relation is sorted, make a key.
Date: Sun, 03 Nov 2002 05:16:11 GMT
Message-ID: <3DC4B0C5.9080407_at_earthlink.net>
Dm. Arapov wrote:
> Jan Hidders wrote:
>>Dm. Arapov wrote: >>>Jan Hidders wrote >>>>[...] >>>>So can you statically type the set union? >>> >>>Pardon me, I do not understand the question. >> >>If I call union(A,B) this should preferrably only be well typed if A and B >>have the same type. Is this decided at compile time?
>
> Sure. RTL checks if a relational operation is valid in compile-time. All
> checks and schema computations are done in comile-time. In compile
> time we calculate list of colums of result, sort order, check if
> colums, on which relation is sorted, make a key.
So dynamic queries are out of the question - or have to be resolved by compiling new code and then either dynamically loading the new code or running a new program? And you cannot write a generic query program that can be run against any tables in any database without either prior knowledge of what is in the database or access to a compiler?
-- Jonathan Leffler #include <disclaimer.h> Email: jleffler_at_earthlink.net, jleffler_at_us.ibm.com Guardian of DBD::Informix 1.00.PC2 -- http://dbi.perl.org/Received on Sun Nov 03 2002 - 06:16:11 CET