Fetch data from another app

Fetch data from another app

I have two apps, Warehouse Database and Pricelist Master Database.

In  Warehouse Database I have a form called Orders and in  Pricelist Master Database  I have a form called ContactForm.

I have created a Lookup in Orders called input.Company which fetches the Customer name from ContactForm.
What I want to do is then using this link fetch the remaining data such as address / customer no. etc and populate fields in Orders.

I know how to do this in the same app between two forms, I use something like:

t  =  Price_List_2014  [ID == input.TG_Code];
input.Price_Column_1 = t.Column_1_Price;
input.Price_Column_2 = t.Column_2_price1;
input.Price_Column_3 = t.Column_2_price;
input.P = t.Column_4_price;

But when I try to do the same thing for two apps, it wont recognise either the app or the form:

r  =  Price_List_Master_Database.ContactForm  [ID == input.Company];
input.Address = r.Address;
input.Contact_Number = r.Contact_Number;

I presume the syntax is wrong for the app / form name, can anyone help please?