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Re: db Model and EOModel
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Re: db Model and EOModel


  • Subject: Re: db Model and EOModel
  • From: Jean-François Veillette <email@hidden>
  • Date: Sun, 23 Mar 2008 08:47:13 -0400

First: most problems I have to solve (actually almost all of them) do not imply concurrent write access to a single object ... so I think I only needed it once (or very few times).

Talking about rules of thumbs ...
- If you really need to avoid overwriting changes made by others, optimistic locking might not be enough anyway (the padlock on the eoattribute). You still need to handle the fact that eof will update your ec with changes made in another ec (after that ec have saved). ... EOF was designed with a single user application model (Openstep-EOF app at the time), unfortunately this model, unchanged, have deficiencies once applied to a multi-user application paradigm (how we use it in WO nowadays).
<rant>Fix the design first (that's not to say that the implementation can't be made working).</rant>


- I never use it (almost) and remove the padlock for almost everything.

- If I have to be careful about concurrent write access, I will look for another, more complete solution and not only rely on the padlock.

- jfv

Le 08-03-22 à 10:07, James Cicenia a écrit :

You know this has always been a mystery to me. I rarely get optimistic locking errrors.. about one a month, so haven't worried too much about it. But is there a rule of thumb about which attributes should have it turned on, and, why when you create an attribute it is always on?

Thanks
James Cicenia

On Mar 22, 2008, at 8:51 AM, Jean-François Veillette wrote:

In addition to the good comments from Guido, I would also point out that all your attributes are set for 'optimisting locking' (the padlock). You probably do not want that. In fact, considering that you might not have the time to deal with locking problems, you probably want to remove them all just to avoid troubles and keep things simple (even if not correct) in this context. It you get spare time at the end, you can always get it right.

- jfv

Le 08-03-21 à 23:46, Gustavo Pizano a écrit :

Ok so here it is my db model and my EOModel, what do you think? is it good? the relations in EOModel? I dunno if i did it good in EOModel based n the db design.

Regards

Gustavo<Convocationwo.eomodeld><modeloRelacional.pdf> _______________________________________________

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References: 
 >db Model and EOModel (From: Gustavo Pizano <email@hidden>)
 >Re: db Model and EOModel (From: Jean-François Veillette <email@hidden>)
 >Re: db Model and EOModel (From: James Cicenia <email@hidden>)

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