Object linking and embedding database connectivity is oledb. And this is used for relational and non relational database like sql, oracle, excel, raw data files. Oledb is successor to odbc not require setup of dsn
What is odbc?
Open database connectivity and this is used for relational databases like sql, oracle and dsn need to be installed for client to access. User/system dsn setup is required using sql driver or other database drivers. And it’s connecting to data source and other things