Re: Does Codd's view of a relational database differ from that ofDate&Darwin?[M.Gittens]
Date: Fri, 17 Jun 2005 17:55:43 +0200
Marshall Spight schrieb:
> Alexandr Savinov wrote:
>>I still do not want to write joins.
> If you really don't want to do joins, and you're willing
> to give up expressive power to achieve this, simply limit
> yourself to querying one table at a time.
If you want to use joins then why you do not use assemply language for programming with even more expressive power? Why to restrict yourself by tables and joins? Manipulate data at byte and bit level - it provides even more freedom.
> But your desire to avoid joins is misplaced. What would you
> say to someone who wanted to avoid projection? What would
> you say to a programmer who wanted to avoid iteration?
>>You propose to implelent it at the user interface level >>but I would prefer to have more support from the database. For example, >>the database should know about alternative paths, which are represented >>in a way different from explicit joins. One approach consists in >>specifying an intermediate table in the path. In this case the qurey >>might look as follows: >> >>get all houses related to 'Smith' via HouseEnsurance
> select * from Houses natural join HouseInsurance natural join People
> where Name = 'Smith';
No. It will take sligtly more space to write such a query. Assume that you have 1000 tables among those 10 need to be involved into the query to produce the result set. That is the point.
>>Nice format, is not it? Would not you like to have such a facility?
> I *already* have such a facility; it's just syntax on natural join.
I had such a facility even before you - it is assembly language. We want to make our life easier.
>>So the question is do we really need to have such a freedom which allows >>us (makes it easy) to produce meaningless results?
> We certainly need not to throw out certain queries just because
> we don't see today how they're useful. (Your use of the word
> "meaningless" is incorrect; all RM queries are meaningful, you
> just might not need that particular meaning at this time.)
In the same sense any sequence of computer commands is meaningful. But why then we are trying to invent new programming approaches and tools? Right. In order to avoid meaningless programs (which are for you meaningful because they can be executed.)
So your notes are rather irrelevant. Or, with the same extent they can be applied to any other approach including the RM.Received on Fri Jun 17 2005 - 17:55:43 CEST