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Re: EOF issues
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Re: EOF issues


  • Subject: Re: EOF issues
  • From: Chuck Hill <email@hidden>
  • Date: Tue, 28 Apr 2009 19:42:58 -0700


On Apr 28, 2009, at 7:31 PM, M.Y. Tjoe wrote:

Hi all,

I am currently investigating an interesting problem. Here is the problem description:

A database table "Person" is represented in EOModel as "Person" with 3 childs "Staff" , "Student", "External". There is type column in Person to tell if he is staff/student/external.

The problem is that when a "External" object is fetched into a ec, changed its type to "student" and saved changes,

You cannot, may not, must not change the type of an object. Look at a Role pattern instead.


Chuck




i.e.

External external = External.fetchExternal(ec, External.ID_KEY, '12345');
external.setType("student");
external.editingContext().saveChanges();


then in the same ec (or different ec) the now "student" still being recognized as External somehow.

When you do

Student student = Student.fetchRequiredStudent(ec, Student.ID_KEY, '12345');
or even
Person student = Person.fetchRequiredPerson(ec, Person.ID_KEY, '12345');


An databaseContextFailedToFetchObject exception is thrown.

I am thinking the objects graph is now broken because Staff Object supposed to be vanished from the graph but it didn't.

Any idea??

Regards,
Harvey

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-- Chuck Hill Senior Consultant / VP Development

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  • Follow-Ups:
    • Re: EOF issues
      • From: "M.Y. Tjoe" <email@hidden>
    • Re: EOF issues
      • From: Ken Anderson <email@hidden>
References: 
 >EOF issues (From: "M.Y. Tjoe" <email@hidden>)

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