Make a connection to a local database connection string

Hello everyone, I'm trying to make a VB console app to send mails extracting the data for the mail from a database located in the same pc. I didn't set up anything of the mysql server client. it was all set up when i bega working on it. I don't know what connection string i should use. I cannot intall visual studio on that computer neither. it's just too old.
I'd like to make a local connection to that database. I have a POS that will make an insert query, a trigger on the database that call this program as I am unable to make mailing work on neither of them but as i don't know which connection string i should use i am getting dumb errors.
I also checked on the sql server connection strings for local DB and they say something like "this method is deprecated since sql server 2012" but they don't mention that method, just the new one.