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Re: Mapping multiple EOs to one table
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Re: Mapping multiple EOs to one table


  • Subject: Re: Mapping multiple EOs to one table
  • From: Ray Ackland <email@hidden>
  • Date: Wed, 20 Aug 2003 14:25:53 +1200

Chuck, Jonathan,

I realise your knowledge comes from having experienced the problems posed by EOModeler, where mine is mostly from a book. I also must admit that I am not as optimistic as I used to be about success. However this exercise is helping me learn a lot more about the hidden complexities and how I've only been reading about the iceberg's tip.

Also as I feel the frustration of coming so close, I get a clearer picture of the smaller details. And I still get confused.

On one hand, I think that EO should not care that a database row is pretending to be several objects as EO is just getting data returned; and I also start to see complications caused by trying to fool EO without fully understanding the fine print.

In any case, I thank you for your comments. If I had thought of doing it as an inheritance hierarchy on my own, I would now be here asking why it wasn't working.

/* several hours of trying things occurred here */

From what I have experimented with so far, the results are interesting. It seems like it will work - as long as you are showing the same fields from the different entities. When I add another field (one which is in one entity, but not the other) sometimes it works and sometimes not (ie depending on which entity you add too, even though they are both children of the parent, and should be equals).

I am *starting* to understand now what Chuck was referring to about them being unique in an inheritance hierarchy. It works like EO brings in not one entity to represent the child, but rather the parent and child entities - each one holding its part of the data. This is where complication occurs as the globalIDs conflict because it is based on a PK and the entity type and ....

Well, I am still trying to figure these things out. But thank guys for your support and guidance. I could have taken your advice to start with, but I'm glad I have given things a go for myself.

ray

On Tuesday, Aug 19, 2003, at 12:48 Pacific/Auckland, Chuck Hill wrote:

They are also unique (must be!) within an inheritance hierarchy based on
the root Entity. Go ahead, try it!


Don't put too much faith in the accuracy of the finer details of those
docs. That's a mid-level overview. There is more that is not documented
than there is.



Chuck


On Wednesday, Aug 20, 2003, at 04:19 Pacific/Auckland, Jonathan Rochkind wrote:

I guess the only way to know is to try it out. My experience with EOF leads me to be very cautious for the same reasons Chuck is. I'd be willing to bet that it won't work, if the goal is what I think it is. But apparently Chuck and my arguments have been unconvincing to others. :) So, sure, try it out. If it works, be sure to let us know; that's be great.

--Jonathan
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  • Follow-Ups:
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      • From: Ricardo Strausz <email@hidden>
    • Re: Mapping multiple EOs to one table
      • From: Chuck Hill <email@hidden>
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 >Re: Mapping multiple EOs to one table (From: Chuck Hill <email@hidden>)

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