Need advice connect backoffice

Hello,

I just need some advice on the following issue.

I want to connect an back-office CRM system to connect to my ColdFusion web application. I don't know if it matters but the backoffice system is using Oracle and my web application is using MS SQL. Also the back office system is in the company network, while the webserver is at an external hosting company.

I just want to know, on a high level basis, which steps I need to take. Also website or articles about this issue are much appreciated.

Thanks,

Samall