Fix dictionary mapping

Classes/NSManagedObject+Mappings.h

@@ -61,4 +61,11 @@
  */
 + (NSString *)primaryKey;
 
+/**
+ Remote key for primaryKey. E.g., @c @@"remote_id".
+
+ @return A remote key name or primaryKey if not overriden
+ */
++ (NSString *)remotePrimaryKey;
+
 @end

Classes/NSManagedObject+Mappings.m

@@ -59,8 +59,17 @@ + (id)objectOrSetOfObjectsFromValue:(id)value ofClass:class inContext:(NSManaged
     if ([value isKindOfClass:class])
         return value;
 
-    if ([value isKindOfClass:[NSDictionary class]])
-        return [class findOrCreate:value inContext:context];
+	if ([value isKindOfClass:[NSDictionary class]]) {
+		NSString *primaryValue = value[ [class remotePrimaryKey] ];
+
+		if (primaryValue) {
+			NSManagedObject *object = [class findOrCreate:@{ [class primaryKey]: primaryValue } inContext:context];
+			[object update:value];
+			return object;
+		}
+
+		return [class findOrCreate:value inContext:context];
+	}
 
     if ([value isKindOfClass:[NSArray class]])
         return [NSSet setWithArray:[value map:^id(id object) {
@@ -116,4 +125,8 @@ + (id)primaryKey {
                                  userInfo:nil];
 }
 
++ (NSString *)remotePrimaryKey {
+	return [self primaryKey];
+}
+
 @end