A better way so save datasets with relations?

Hi Group,

again a rookie question :-( Sorry for that.

I have created two entities in my application:

EOCategory (which stores a category) and
EOKeyword (which stores a keyword of a given category)

EOCategory {
   id (primary key)
   category (varchar)
}

EOKeyword {
   id (primary key)
   keyword (varchar)
   fiCategory (id, foreign index of the category)
   category (relation, which defines an 1:1 relation between  
EOKeyword.fiCategory and EOCategory.id)
}

so far I think this is the correct way to define a relation in  
EOModeler.

When I want to save a new Keyword I have to do the following:

EOEditingContext ec = session().defaultEditingContext(); // retrieve  
the EC
EOKeyword newKeyword = (EOKeyword)EOUtilities.createAndInsertInstance 
(ec, "EOKeyword"); // create and insert a new instance of EOKeyword
newKeyword.takeValueForKey(newkeyword, "keyword"); // set the keyword  
with a value from a web form
NSDictionary result = EOUtilities.primaryKeyForObject(ec,  
categoryObject); // retreive the primary key of the related category  
object
int pkey = ((Integer)result.objectForKey("id")).intValue(); //  
retreive the primary key of the related category object
newKeyword.takeValueForKey(new Integer(pkey), "fiCategory"); // set  
the foreign index in the EOKeyword instance
newKeyword.addObjectToBothSidesOfRelationshipWithKey(categoryObject,  
"category"); // add the relation to the EOKeyword instance


In the beginning I thought that it should be sufficient to set the  
keyword and to use addObjectToBothSidesOfRelationshipWithKey to set  
the relation because I would expect, that  
addObjectToBothSidesOfRelationshipWithKey takes care of the foreign  
index attribute of the entity. But this didn't work. I always got an  
exception which occured during the validation of the foreign index.

Is this the right way to save a dataset with a relation to the  
database? I doubt that.
Could someone give me a clue what I can do better?

Thanks in advance,

Helmut

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