Re: Passing an EOGenericRecord Refrence in a Direct Action
Re: Passing an EOGenericRecord Refrence in a Direct Action
- Subject: Re: Passing an EOGenericRecord Refrence in a Direct Action
- From: Daniel Eggert <email@hidden>
- Date: Mon, 19 Sep 2005 19:58:05 +0200
I think I'll go for this solution. Should be possible to wrap that PK
code up in some nice and cosy java methods.
/Daniel
Mantra: Deliver yesterday, code today, think tomorrow.
On Sep 19, 2005, at 6:48 PM, Chuck Hill wrote:
Me, I'd swallow my lilly white purity inclinations and just expose
the PK in this case. Or don't expose it and use EOUtilities.
primaryKeyForObject(EOEditingContext ec, EOEnterpriseObject object)
to get at it. EOUtilities also has a method to get an object based
on the PK. I don't see any reason to not use the PK in this case,
it has no meaning to the user, just a unique bit of data. You
already have one unique, meaningless bit of data, why add another?
Chuck
On Sep 19, 2005, at 8:44 AM, Daniel Eggert wrote:
On Sep 19, 2005, at 4:46 PM, Arturo Perez wrote:
Daniel Eggert wrote:
Hi,
My App displays a list of items. When the oser clicks on one, I
want to display a bookmarkable direct action with info about
the item.
How do I go about passing a reference to an item (or its
EOGenericRecord subclass instance)?
The primary key is not a class attribute, and the Apple docs say
that exposing the primary keys is a bad idea:
Primary keys and foreign keys should not be marked as class
properties. This is for two reasons: Enterprise objects have
no knowledge of the primary and foreign keys of the tables
from which they are mapped, and these keys are of no use to
your business logic. Also, to ensure that the automatic
primary key generation feature of Enterprise Objects is
properly invoked, primary keys must not be marked as class
properties.
What to do?
/Daniel
You should create an alternate key (which is a technical, RDB
term BTW) to use in your direct action. Add another unique
column to your table or create a mapping table. Any number of
ways to do it.
-arturo
Thanks. Is there an easy way to have either the database or
WebObjects maintain this alternate key? Or do I need to ensure the
uniqueness myself?
The mapping table is a table of unique IDs (that I maintain
myself) and a reference to my item? Or is there someting more
subtle to it?
Was hoping that someone (Apple?) already coded a solution for this
trivial problem.
/Daniel
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