This ADBC - ABAP Database Connectivity is a tool/an interface to execute SQL statement (OO substitute of native SQL statements), but first you need to actually connect database.
For Information on DB connect, look at DB Connect Architecture and reference note 323151 - Several DB connections with Native SQL. Not that Basis will be required to install some component to access a database type distinct from current one (An other manufacturer, e.g. access MS SQL if SAP running on Oracle)
NB: You could also perform some search on UD Connect (uses Application Server J2EE connectivity)
Regards,
Raymond