Michiel Meeuwissen wrote:
Ernst Bunders wrote:
André van Toly wrote:
Op 12-mei-2006, om 11:35 heeft Nico Klasens het volgende geschreven:
This is exactly the point in which MMbase and Hibernate made
different design choices. The hibernate guys will tell you never to
use many-to-many relations anywhere. There is always a better
alternative. MMbase uses many-to-many relations everywhere. But they
both solve the persisitency problem
Is it not true that it is your own choice to use many-to-many relations
while building MMBase applications? You can avoid them and (maybe, we
don't know because there are no tools to measure) build a fast
performing application.
I think the point is that mmbase is allways using a join table (ei the
relation) to join twoo nodes. That is not good for performance. Wat is
really bad is if the same join table is used to join say 5 or 6 steps in
one query. mmbase knows no other way. Specially when you combine this
with crappy database inheritance, the insrel table becomes a problem..
I'd propose the relative small change in query syntax, that you can also
follow node-fields in a 'path' on the cloud. For those kind of relations you
can skip the intermediate insrel then, simplifying the database query.
An MMBase relation object is then a special kind of normal object with 2
node fields, and recognized by query-objects and syntax.
<mm:list path="news;author,people"> or so which would lead to
select .. from news n, people p where n.author = p.number;
in stead of
<mm:list path="news,author,people"> which would lead to
select .. from news n, insrel i, people p where n.number = i.snumber and
i.dnumber = people.p.number and i.rnumber = ..;
shouldn't it be more logical to have something like:
<mm:listnodes type="news" id="n">
<mm:node node="n:author">
<!-- do stuff -->
</mm:node>
</mm:listnodes>
Your syntax seems to suggest that you can access the author without
using the news, which is a bit odd, becouse the author is only relevant
(ie an author) in respect to this news node.
Ernst
Michiel
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