Re: Relationships
Re: Relationships
- Subject: Re: Relationships
- From: Chuck Hill <email@hidden>
- Date: Wed, 1 Oct 2008 21:46:38 -0700
Some generic advice on "thinking in WebObjects".
On Oct 1, 2008, at 7:19 PM, Awbrey Hughlett wrote:
I have a component with an editing context linked to an entity named
Listing.
It is better to think of the EOEnterpriseObjects (usually just called
EOs), not entities, as being "in" the editing context. Think of it
like a sandbox. EOs in one sandbox can be related to EOs in an other
sandbox. They playground referee says so.
I have a WOPopUpButton that is populated from a entity named Basic.
The Basic entity has two attributes: basicID (primary key), and
basicType. basicID has a 'to many' relationship to the basicID
attribute of the entity Listing. When I save the changes to the
editing context, I want the basicID attribute in the selected value
from the WOPopUpButton to populate the basicID attribute of the
Listing entity.
As pretty much a hard and fast rule: "If you are thinking about
primary or foreign keys, you are doing it wrong". Those are artifacts
of the implementation. EOF manages those. Think about objects and
relationships between objects:
I have a WOPopUpButton that is populated from a entity named Basic.
The Basic entity has a name, basicType, that I shown in the
WOPopUpButton. A Listing object can have one Basic, and a Basic can
be used on many Listing objects. When I save the changes to the
editing context, I want the selected Basic object to become the object
in the basic() relationship of the Listing entity.
I can make it work if I make the basicID of both entities a class
property, but I know there has to be a better way using the
relationship I set up (given that I even did that correctly). Does
the method 'addObjectToBothSidesOfRelationship()' have anything to
do with that or am I just way off?
I think Guido pointed you in the right direction.
--
Chuck Hill Senior Consultant / VP Development
Practical WebObjects - for developers who want to increase their
overall knowledge of WebObjects or who are trying to solve specific
problems.
http://www.global-village.net/products/practical_webobjects
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| | >Relationships (From: Awbrey Hughlett <email@hidden>) |