Re: Q: Views with EOF
Re: Q: Views with EOF
- Subject: Re: Q: Views with EOF
- From: Jonathan Rochkind <email@hidden>
- Date: Thu, 8 Apr 2004 11:28:58 -0500
First of all, I think choice 3 and 4 are basically the same as far as
EOF is concerned. In both cases, you will have two entities which
really point to the same underlying table (one through a view; one
quite plainly to the same underlying table). If the same rows can
exist in both entities, your main concern is with object graph
consistency. That is, you have one EO, let's call it simpleEO of
EntitySimple that represents the same db row as another, viewEO of
EntityView. If you make changes to simpleEO, EOF isn't going to know
those changes should apply to viewEO too---so even though they are
really representing the same row, they could get out of synch. Which
might also have implications for optimistic locking, as well as of
course just for your application logic, and what gets shown to the
users.
I can't think of any other problems than that consistency one, but
I'm not sure if there are any other sub-problems that consistency
problem might cause. And I don't think it makes a difference if it's
possibility 3 or 4 below, I think both have pretty much exactly the
same situation in regards to EO consistency. I'm not neccesarily
saying you shouldn't do it, though; it should basically work subject
to that limitation, if that's acceptable.
If you _didn't_ have the actual table exposed, and only had an entity
pointing to the view---I think this would be fine. (So long as your
db allows updates to views! Some do and some don't. Of course if it
doesn't, than this view entity would have to be read-only).
Likewise, if you _only_ had an entity with a restricting qualifier,
and not another one pointing to the same table without a restricting
qualifier---no problem.
--Jonathan
At 12:05 PM -0400 4/8/04, Arturo Pirez wrote:
Hi all,
Here's a question regarding views and EOF. I have an entity with a
toMany relationship to some other entities. At this junction, I
need to either
1) put in a filtering everywhere I traverse this relationship
2) make cover methods to run the SQL I need to filter these
relationships
4) create a new entity with a restricting qualifier and
relationship to that
3) Create views instead of tables to fulfull these relationships.
I much prefer method #3 over the others. However, I would like to
approach this cautiously. Are there any gotchas in defining EOF
relationships with views instead of tables?
Thanks in advance.
----
WO in philadelphia - wanna cheesesteak with that?
Please visit webobjects.meetup.com.
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