Peter Rabbitson wrote:
On Sun, Jul 18, 2010 at 02:40:47PM +0200, Leandro Hermida wrote:
very good points and makes a lot of sense. If I can ask a more general
question then, why do ORMs exist in the first place and why are they so
popular vs using a object persistence mechanism? There must be some serious
advantage to using them.
Because there yet does not exist a persistent object store, that can be
asked to fetch "all objects which have related objects whose attribute X
is Y", and which will do so by *transparrently* using native SQL methods
(namely GROUP BY over a joined resultset). Matt Trout is working on the
foundation of just such a "mapper", but this is a very very hard problem
to get right, so progress is slow.
What are you referring to exactly? "SQL-Abstract-2"? Which last I looked
hadn't had any version control activity in a year? Or something else? Url?
Separately ...
Following up my prior post, referencing a talk given yesterday,
http://thebuild.com/blog/2010/07/18/orms-and-their-discontents-2/ , one of the
interesting points raised that I recall is that ORMs typically start simple and
address the desire of an application programmer to just save an object to disk,
and they don't want to know SQL.
And then the ORM gets more complicated as actual business requirements set in,
such as "okay, great, now I need a report of customers of who have paid at least
50% of their balances", and then the ORM's API eventually just becomes a
proprietary alternate syntax of SQL, in order to meet the user's needs that they
would otherwise have written in SQL, and so the users haven't really avoided
having to know something about SQL after all.
Interesting talk, and just a few dozen slides.
-- Darren Duncan
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