NSLog a message when NSManagedObject Class's name is not as same as the entity's name in the CoreData Model.

Classes/NSManagedObject+ActiveRecord.m

@@ -142,6 +142,9 @@ + (NSFetchRequest *)createFetchRequestInContext:(NSManagedObjectContext *)contex
     NSFetchRequest *request = [NSFetchRequest new];
     NSEntityDescription *entity = [NSEntityDescription entityForName:[self entityName]
                                               inManagedObjectContext:context];
+
+    if (entity == nil) NSLog(@"There's no entity named \"%@\" in your CoreData model. Please confirm the %@ class's name is as same as the related entity in your model. Or you can set the entity name by using \"+ (NSString *)entityName\" in your subclass.",[self entityName],[self entityName]);
+
     [request setEntity:entity];
     return request;
 }