I am working on a project in which I am assigned to implement database first Approach. Here, I want to know that when we initiate database first approach we map that to an existing DB, but what if I have another DB with the same structure but different data, can I use that DB by just changing the connection string ? or will it impact somehow?
It will work when you change the connection string. I recommend you select the 'Code First from database' when creating new 'ADO.NET Entity Data Model' with VS add new item.