connect_string
The connect_string is a normal connect string that may or may not contain server and database information.
connect_to_db
If connect_to_db is non-zero (TRUE), then the function attempts to connect to a database on a server. It returns TRUE only if the connect
string is sufficient to connect to the named database on the named server.
connect_to_db
If connect_to_db is zero, then the function only attempts to locate a server. It returns TRUE only if the connect string is sufficient to
locate a server. It makes no attempt to connect to the database.