Core Data setPrimitive-setter causes EXC_BAD_ACCESS
===

when I try to set the variable `eventId` of my `NSManagedObject (Event)` I get ther error `EXC_BAD_ACCESS`. 
I don't know the reason.

Here's the code of my class `Event`

    @interface Event : NSManagedObject 
    
    @property (assign)              NSInteger   eventId;
    
    @end


    @interface Event (PrimitiveAccessors)
    - (NSInteger)primitiveEventId;
    - (void)setPrimitiveEventId:(NSInteger)event_id;
    @end
    
    
    
    @implementation Event
    @dynamic eventId;
    
    ...
    
    -(NSInteger)eventId
    {
        [self willAccessValueForKey:@"eventId"];
        NSInteger id = [self eventId];
        [self didAccessValueForKey:@"eventId"];
        return id;
    }
    
    -(void)setEventId:(NSInteger)event_id
    {
        [self willChangeValueForKey:@"eventId"];
        [self setPrimitiveEventId:event_id]; //Here I get the error
        [self didChangeValueForKey:@"eventId"];
    }
    
    ...


Anyone can solve the problem?

Thanks for help