Asterisk can store CDR data in a local or remote database via the ODBC interface. The cdr_odbc.conf file contains the information Asterisk needs to connect to the database. The cdr_odbc.so module will attempt to load the cdr_odbc.conf file, and if information is found for connecting to a database, the CDR data will be recorded there.
If you are going to use a database for storing CDR data, you will have to select one of the many that are available. Asterisk does not like having multiple CDR databases to connect to, so do not have extra cdr_.conf files hanging about your Asterisk configuration directory.