Re: Expanding Import
Re: Expanding Import
- Subject: Re: Expanding Import
- From: "Jerry W. Walker" <email@hidden>
- Date: Tue, 7 Mar 2006 22:22:25 -0500
Hi, Scott,
On Mar 7, 2006, at 8:16 PM, Scott Winn wrote:
Thanks much to everyone for the help. Let me know if anyone hears a
good rule of thumb for what does and does not need a relationship.
I think the primary rule of thumb is never add bi-directional
relationships to reference data, e.g. names of states, names of
months, etc. (well, hardly ever and you better have a darn good
reason if you do).
If there is a primary rule of thumb, that's it. But it gets a bit
more complicated than that.
Chuck suggested: "In a nutshell, avoid relationships from lookup
objects to transactional objects."
In my experience, however, I've seen two approaches to all but the
primary rule of thumb above.
One says put all the relationships in your model as bi-directional
and prune them only if (and when) they cause problems. This approach
tends to make your initial coding easier because you can simply
assume, for any but a relationship to reference data, that the
relationship is bi-directional and use it as such (in the WO
way :-) ) without thinking about it a lot. When you find a problem,
as you have, determine the offending relationship and prune it. This
approach tends to be followed by the "Make it work, make it right,
make it fast" school of developers.
The other (followed by strong XP advocates) says to only add
relationships, and only in the direction required, that are needed to
complete the immediate requirement. Never add anything (relationship,
attribute, method, class and so forth) for some ill defined future
need. In XP terms, only add what's needed to implement the current
story and nothing more.
I've used both approaches and found them about the same in result
unless you know you're working on a high volume, heavy traffic site
(like the iTunes Music Store...), then you generally have to be aware
of the inefficiencies of every WO trick you use.
HTH.
Regards,
Jerry
--
__ Jerry W. Walker,
WebObjects Developer/Instructor for High Performance Industrial
Strength Internet Enabled Systems
email@hidden
203 278-4085 office
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