DBD is a common prefix for all perl modules used as database drivers by the DBI module. These drivers hide the internals of different relational database management systems by providing a common API through the DBI module.
Access to relational databases in Perl is usually accomplished by the CPAN DBI module. See also DBI tag wiki entry.
DBI provides a common API for database access that uses separate drivers (DBD::*) internally to handle the specifics of different database management system implementations.
Some of the most popular DBD modules available on CPAN are:
DBD::MySQL
DBD::Oracle
DBD::Pg (PostgreSQL)
DBD::ODBC
DBD::SQLite
DBD::Informix
DBD::Mock (for testing purposes)
DBD::CSV (limited SQL access for CSV files)
DBD::JDBC
