Re: EO model validation with Wonder and foreign keys

So am I correct in stating the rule as: if an EOAttribute is a source  
attribute of any EOJoin in any relationship in the attribute's parent  
entity, then it must not be a class property?  Is there actually a  
justifiable reason for this, or is this a framework bug that PW can  
maybe fix?

ms

On Dec 13, 2006, at 4:55 PM, Chuck Hill wrote:

>
> On Dec 13, 2006, at 1:20 PM, Zak Burke wrote:
>
>> Zak Burke wrote on 12/12/06 7:32 PM:
>>> I thought I would bite the bullet and install Wonder, to see if  
>>> it made all my EO Model/Entity Modeler validation issues  
>>> magically disappear. I've written about this problem before but  
>>> was never able to resolve it. Here it is, in a nutshell: When an  
>>> EO has a required relation, Entity Modeler complains if the EO's  
>>> foreign key is not also marked as required. EOF, however, chokes  
>>> when the foreign key is required because it handles validation  
>>> before a new related object has been persisted, and therefore has  
>>> no foreign key to assign.
>>
>> Well, I managed to solve this.
>>
>> The problem only appears if the relationship's foreign key is  
>> accessible as a class property. If the foreign key is not a class  
>> property, then apparently EOF never gets access to the property to  
>> notice that fact that it's empty. That kinda makes sense, but in  
>> an ostrich-like way. (If I don't look for a value that isn't  
>> allowed to be empty, it must not be empty! Hooray!)
>>
>> I understand how my model caused this to occur, but it seems like  
>> the model should throw an error whenever a property used as part  
>> of a relationship is exposed as a class property.
>>
>> I know some modeling wonks will flame me about how PKs and FKs  
>> shouldn't be exposed anyhow and I could have avoided all these  
>> problems if I had just followed recommendations about what fields  
>> to expose. IMNSHO, the recommendation ought to be a rule because  
>> violating it causes an error. At the very least the documentation  
>> should explain the consequences of ignoring it.
>>
>> Ah well; at least now I understand.
>
> Then allow me to confuse you.  :-P  I have a large project with the  
> PK exposed all over the place.  Bad or good, that is the way it  
> is.  It does not cause problems.  Only exposing the FK seems to  
> cause this problem.  I do agree that having a validation for this  
> in Entity Modeler is probably a good thing.
>
>
> Chuck
>
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> problems.
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