If the development tool does not support creating the connection via an interface, if it needs manual entry for the connection string, and if you cannot remember the elements required for making the connection string, obviously you have to make a search for finding it. But, do you know that there is an older technique for making the connection string?
Here is a simple solution for that. All you need is a creating an UDL file (Universal Data Link), make the connection for required database, and get the connection string added to the file related to the connection you made. This support comes through Microsoft Data Access Component (MDAC) and it provides you a common interface for inputting required information for the connection.
Here are steps for creating an UDL file and getting the connection string.
Create a text file and change the extension as udl.
Double-click on the file for opening the interface and input information for the connection.
Save it and open the udl file using a text editor, you have the connection string required.