And I would add modeling your business because of the UI is not a good sign, even with D2W (except implementing userPresentableDescription)
Philippe --------------------- http://twitter.com/prabier Sent from my iPhone > On 04 Mar 2014, at 19:57, Chuck Hill <ch...@global-village.net> wrote: > > > > On 2014-03-04, 10:17 AM, "David Avendasora" wrote: > > Yikes! > > So, if I’m reading this right, you have a class property of “classe()” and > *also* a flattened class property of “lycée()” and you made the (Model) > change to make creating the UI (View) more convenient. Is that right? > > If so, you are asking for all kinds of trouble. > > Almost demanding trouble. > > > Have you verified that calling setLycée() also changes the value of > classe().lycée() because I’m not entirely sure it always will, especially if > you have a UI that shows both. Having multiple paths to the exact same column > in the database is very dangerous and completely non-deterministic in the way > in which it will fail. > > Actually, I’d guess that it will pretty deterministically fail as there are > two copies of the data. > > > Chuck > > Sometimes it will work as you expect, other times it will simply not use the > new value, other times you will get optimistic locking failures (IF you have > locking turned on on the FK). > > This is guaranteed to happen if you have FKs marked as class properties, but > I can see it happening here too. The reason flattening works with > many-to-many relationships is that the relationships to the join table are > NOT class properties. > > Dave > > On Mar 3, 2014, at 2:25 PM, Ray Kiddy <r...@ganymede.org> wrote: > > On Sun, 02 Mar 2014 16:05:26 +0100 > Jean Pierre Malrieu <jp.malr...@free.fr> wrote: > Actually I think I solved the problem by using the relationship > keypath in the qualifier: > if ( cd.toOneRelationshipKeys().contains(sv1)) { > EORelationship relation1 = entity.relationshipNamed(sv1); > v1Qual= new EOKeyValueQualifier(relation1.relationshipPath(), > EOQualifier.QualifierOperatorEqual, record); } > NSArray objectsInRow = > EOQualifier.filteredArrayWithQualifier(relevantObjects, v1Qual); > That seems to work. > So, it seems that you fixed the problem by not accessing the > relationship via the flattened path. That would work. > Flattening a to-one relationship is possible, though certainly not the > common use case. > It is likely that you fell afoul of the rule that the inner > relationships in the chain of the flattened relationships should not be > class properties. If you took a set of to-one relationships that were > not class properties, you can flatten them. It would just be strange to > create the to-one relationships in that manner. > When I have a common path through some set of relationships, I usually > provide support for that in the class by creating a final static of the > qualifier, or add methods to get across the set of joins, or both. > - ray > Le 2 mars 2014 à 14:39, Philippe Rabier <prab...@me.com> a écrit : > I don’t understand why you try to flatten a to-one relationship. > You can flatten an attribute or a many2many relationship. > Instead of calling classe().lycée(), I can just call lycée(). > It is also useful to me because I I dynamically present the relations > to the user for selection in a popup menu. So I need a direct > relationship to Lycée. > Creating a many2many relationship is pretty straightforward: when > you create a relationship between 2 entities, you choose to many on > both sides, give a name to the join entity and check “flatten”. > Regarding your code, I don’t get you when you say “not work well > with this relationship”. Is it the one to try to flatten? If you > have issues with the relationship, it’s not surprising you don’t > get the expected results, right? > Why the test "if ( cd.toOneRelationshipKeys().contains(sv1)) "? I > suppose you get an exception before if sv1 is not a valid > relationship key… > Because I build different qualifiers if the relationship is a to-many > (I didn't show it in the code I sent, because it is not relevant). > And I’m a bit surprised you still use accented characters (Lycée). > That’s something I would never play with… > You are right, but this is D2W app, and I thought it would save me > writing a lot of displayNameForProperty rules. > Thanks for >
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