Hi guys , I'm getting my feet wet with developing my order management applications for integration with google apps. However there are certain aspects I need to take into consideration prior to proceeding any further.

My application is such that it would upload documents to google documents and store contacts in google contacts. It requires such that a single order can have a number of uploaded documents associated with it as well as some contacts associated with it. MY question however is what would be the most efficient way to implement this.

I could keep key tables for both contacts and documents which woudl contain just an ID and link to the documents/contacts or their respective identification id on google.

Or I could maintain an exact replica of the information on my own database as well as a link to the contact on google. However won't that be too redundant. I don't want my application to be really slow as I'm afraid that everytime I make a call to google docs to retrieve a list of documents or google contacts it would be really slow on my application - or am I getting worried for no reason?

Any advice would be most appreciated.