Re: Inheritance...
Re: Inheritance...
- Subject: Re: Inheritance...
- From: David Avendasora <email@hidden>
- Date: Thu, 8 May 2008 13:08:19 -0400
How will it work for Wonder's "Partial" Entities that are part of a
Vertical Inheritance structure on a full moon with Pluto in the third
house?
On May 8, 2008, at 12:51 PM, Chuck Hill wrote:
On May 8, 2008, at 7:14 AM, Florijan Stamenkovic wrote:
Besides the question below, I came up with another scenario
today... While it is true that performance should not be an issue
with the records in the inheritance tree, what about relationships?
I will have potentially thousands of records that have two
mandatory relationships to the leaf nodes, but defined in the model
as relationships to the root of the inheritance.... Those
relationships will be used heavily, and I will need to pre-fetch
them. So, when that happens, what is going on in the database, when
using horizontal inheritance? There is an FK in the table I am
fetching on, but that FK might resolve to a PK in any of the
inheritance tables, no? Sounds kind of expensive... Or is there
something magical going on?
For Horizontal, it will issue one select for each leaf entity
(IIRC). Single table is much more efficient in this scenario.
Chuck
F
On May 07, 2008, at 22:24, 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
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