What is SID when connecting silk central with SQL Server?

Question

I am trying to connect silk central application to a SQL Server database. Once I am on the database connection page of silk central, It will ask for following information.

DBMS type: 
Port:
Database/SID: 
Username:
Password:  

What to fill in Database/SID, username and password field ?

DBMS type: SQL Server  
Port: 1433
Database/SID: ?
Username: ?
Password:  ?