Connection is the process of linking your website or web application to the mysql database. So it cannot be a data within the database. The login & password or Signup details can be part of the database but not the connection.

Java code for tax deduction in database connection?

Connection Database can be established using language such as Java. For that you need to create an object of Connection type.

Activex data object Database connection Activex data object Database connection

No, if you run a database on localhost, and you are the only one to edit it from your local pc... but if you want others to read/write to the database you will need an internet connection.