How to make Proxy of NSManagedObject subclass?

I have a class "Make" which is subclass of NSManagedobject which contains attributes

1-Nsstring*name

2-Nsset*models

As my Model has relationship like this

Quotation<-QuotationItem<-Plan<-Asset<-Make

Make object is rarely used My scenario is When I call webService then MakeCode is received on which I make a query on sqlite DB and get name and models as data is rarely used and I want that data when we just call Make.name; Dynamically load data from sqlite and fill my CoreData make entity Keep in mind I want to keep all the db handling in another class So I decide to make a "Proxy object" which will give me data when I needed but its not working on my side

Did any one of you make ever make a proxy of NSmanagedobject subclass ?

I can make category on Nsmanagedobject but I don't want to do this.

Kindly Help.