Re: How to handle relationship properties?
Re: How to handle relationship properties?
- Subject: Re: How to handle relationship properties?
- From: Miguel Arroz <email@hidden>
- Date: Sun, 1 Jan 2006 21:33:12 +0000
Hi!
I have tried something like that, but I'm having a (probably
stupid) problem... the problem is that I cannot access the
relationship! I must be missing something obvious, but how do I say I
want the relationship for THAT user and for THAT file? The
EOSpecification only allows stuff like user email, user name, etc,
and I needed a way to specify a user using it's object, and not one
of its attributes. The problem is that on some classes the attributes
are not enough to identify an object, as there may exist different
objects (accounts, etc) with the same name. The only difference
between them is their ID (primary key on the DB), that is hidden from
the Java layer.
Remember that these are many-to-many relationships, so I cannot
just access the user.file key...
Yours
Miguel Arroz
On 2006/01/01, at 16:48, Arturo Pérez wrote:
On Jan 1, 2006, at 9:53 AM, Miguel Arroz wrote:
Hi!
Imagine I have the following scenario:
- An entity "user".
- An entity "file".
- A many-to-many relationship between both.
Now, I want to store something like the access permissions a
user have over each file. The obvious way to do that is storing
that data in the relationship itself. What's the best way to do
that in WebObjects? The problem is that the userFile record is
only created when inserting the "user" and "file" records in the
DB, so I cannot access it (and change it) before a save. But if I
save, I get an error that I'm violating the non-null constraints.
Of course, I may drop the non-null constraint, but this seems a
bit ugly to me...
How do you guys do this kind of stuff?
The obvious way is the correct way. In this situation, one cannot
use flattened relationships as one needs to access the relationship
directly. Other than that, there's no trick to it.
Set up User, File and UserFile EOs, create&instantiate all three,
and use addObjectToRelationshipWithKey to connect them up.
-arturo
"The world lies in the hands of evil
And we pray it would last" -- Apocalyptica, Life Burns!
Miguel Arroz
http://www.ipragma.com
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