I'm a new developer and I'm working on a project that utilizes the SalesForce REST API. A portion of my .Net project involves updating the web.config and the database depending on the login credentials. 

For example, client 1 logins in, the are updated with the correct Consumer Key and Client Secret. This client has access to Database1. 

Client 2 logs in. are updated appropriately. Now, the Database1 is switched out with Database2, programmatically. 

Is there a way to programmatically change the database source depending on login?

---

Quick edit to my post. Client1 and Client2, in this instance, are two separate companies, that should not have access to each other's databases. I want to be able to utilize the same application for both clients, but update the web.config and the database used, depending on which company logs in.