Re: Inheritance...
Re: Inheritance...
- Subject: Re: Inheritance...
- From: Ken Anderson <email@hidden>
- Date: Thu, 8 May 2008 10:04:02 -0400
If you're only going to fetch on the leaf entities, I would favor
horizontal just from an organizational point of view. Remember
though, if you have relationships to the root entity (like the inverse
of a to-many relationship that all subentities have), you're still
going to have extra fetches when the fault fires.
On May 7, 2008, at 10:24 PM, Florijan Stamenkovic wrote:
Thanks everyone from preventing me to learn the hard way...
Apparently my choices are single-table or horizontal.
A question: assuming I intend to perform individual fetches for each
entity anyway, that there will be no direct fetching on the root
entity, and that there will be maybe 100 records in the total
hierarchy, is there something else against using horizontal? It
seems that, considering these things, it might be profitable to keep
the db clean, even though at the moment only EOF will deal with
it... I mean, for 100ish records in total, how bad can performance
get???
30+ columns in a table just hurts me in the stomach area :) Though,
I guess I could, arghhh, get over it...
Flor
On May 07, 2008, at 16:08, Mike Schrag wrote:
You might want to check for suicide exclusions in your life
insurance policy. :-) David Avendasora was using Vertical with
JC. He stopped. Maybe he can provide some pointers. My advice
would be to ignore that "Subentities will have a sufficient amount
of their own properties" and use Single Table. Or, failing that,
Horizontal. Vertical is the least efficient and the least used
hence has a higher probability of bugs.
I would recommend AGAINST horizontal here -- You have 10 entities
in your hierarchy, which means 10 fetches every time you need to
fault an object of the root entity. I second Chuck on using single
table. Yes, your database is uglier, and you lose some of the
benefits of database not-null constraints, but this is really more
of an issue if other apps are using your database. For us, it's
almost never the case .. our WO apps get exclusive access to the
dbs generally, so as Chuck as said, the database is an
implementation detail. I let EOF worry about the fact that it has
a lot of columns.
There ARE people using vertical, but I only know of a handful.
ms
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