What is an odbc connection?

Answer 1

ODBC abstracts the database from it's physical location, and makes it available over a network. Basically, it makes it so you can work locally or remotely with a database without worrying about the details. It also abstracts the details about exactly which type of database you are working with (to a degree). Thus, you can build an application with Access, import the data into SQL server, and just re-assign your ODBC connection, and your system will work almost identically, although faster. The only information your application needs is the DSN (Data Source Name), which is a unique name you choose for every ODBC connection created.