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Re: EOF Stumper (for me at least)
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Re: EOF Stumper (for me at least)


  • Subject: Re: EOF Stumper (for me at least)
  • From: Daniel Beatty <email@hidden>
  • Date: Sun, 24 May 2009 15:28:38 -0500

Greetings Dino,
You are absolutely right. I have noticed a similar issue in vertical subclassing an object that has a many to one relation in it. I shall provide an example, hopefully PDF pictures from OmniGraffle are permitted. This model is motivated by "Cloud Computing Security," which will hopefully no cloud the subject.


Attachment: pastedGraphic.pdf
Description: Adobe PDF document



Let us say we model this calling participants an object called Subject. Subject has two subclasses: "User Subject" and "Group Subject". When I attempt to subclass "Basic Entity Access" to produce "Federation Access" I see the EO Modeling tool in WOLips providing both the "id" for the parent "Basic Entity Access," "Allow Operations," and "Subject". Furthermore, the column identified for each "id" types is "id" as opposed to what the tool had produced for them such as "permissionsID", "participantID" respectively. The obvious trick around this is use "Horizontal" subclassing.

The point being is that this creates a violation of the multiple primary key commandment of EOF, also. The solution is to do a bit of massaging of the table definitions, or suffer.

Later,
Dan


On May 19, 2009, at 10:48 AM, Ricardo Strausz wrote:

Hola Lon, Chuck...

On May 18, 2009, at 9:05 PM, email@hidden wrote:

Message: 7
Date: Mon, 18 May 2009 17:58:32 -0700
From: Chuck Hill <email@hidden>
Subject: Re: EOF Stumper (for me at least)
To: Lon Varscsak <email@hidden>
Cc: WebObjects-Dev Mailing List List <email@hidden>
Message-ID: <email@hidden>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes

Hi Lon,

This and your other problem cause me to suspect that you are violating
an EOF commandment somewhere. The "it works sometimes and not others"
is often indicative of a violation somewhere. Perhaps in this
process? I am also unsure that Propagate Primary Key is intended to
be used with a partially user controlled PK. I don't know that is
not, but it sounds suspicious.

I agree with Chuck, you are violating an EOF commandment; namely, when you use compound primary keys, you are on your own!


I'd been using Sybase since EOF was in beta, and compound primary keys were always a headache... I am not sure, but my guess is that it is a locking problem.
Now I assign both (or sometimes three or more) keys by hand; indeed, I have as part of my framework an specialised object (BAFolio) just to do that.


If you have the proper protocol (like all PKs have the same "key- structure"), such an object is not hard to implement and you can forget about that problem forever... HIH.

Suerte!


On May 18, 2009, at 2:27 PM, Lon Varscsak wrote:


The worst part of this is that without any code changes sometimes it works and sometimes it fails (meaning sometimes orderLineNumber is written to the adaptor op properly and therefore the database...but not always).

I have changed "propagates primary keys" and propagated it myself by
overriding the setOrderNumber method on OrderHeader (and then
passing it down to OrderDetailSale) and the error goes away
completely.  I'd prefer not to do this as it really does propagate
orderNumber which I want, it just seems to be occasionally trampling
orderLineNumber.



Dino
--
email@hidden
Business Applied X Objects
http://strausz.blogspot.com
(+52-1) 55-5437-8205




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Dan Beatty, M.S. CS (B.S. EECS) Ph.D. Student Texas Tech University email@hidden http://venus.cs.ttu.edu/~dabeatty







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References: 
 >Re: EOF Stumper (for me at least) (From: Ricardo Strausz <email@hidden>)

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