Re: Relation oddity
Re: Relation oddity
- Subject: Re: Relation oddity
- From: email@hidden
- Date: Mon, 26 Jun 2006 20:32:15 +1200
Grüß Wolfram;
Yes, I had a big problem a while ago NOT having some reverse
relations, so i
always have reverse relations. It is absolutely unclear in which
case they
are necessary... (or optional, or recommended, or superfluous...)
If you have a 'to many' relationship for which there may be 1,000,000
EO's in the fault then it is typically quite impractical to actually
use this relationship because the poor system would need to load in
1,000,000 objects all the time! This is a typical scenario where a
one-way relationship (the 'to-one') is a better idea.
Another case where a reverse relationship is bad news is when you
have 'reference data' entities such as "ConsignmentType" for a
"Consignment" EO. In such a situation, the "ConsignmentType" might
be read-only, cache in memory and reside in the 'shared editing
context'. One rule here is that you should not have a relationship
going from entities that live in a regular editing context going into
the shared editing context. So again, a non reflexive relationship
is the way to go there as well.
cheers.
___
Andrew Lindesay
www.lindesay.co.nz
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