"The DBI is a database interface module for Perl. It defines a set of methods, variables and conventions that provide a consistent database interface independent of the actual database being used", explains Bunce, the architect and inventor of DBI. He and Descartes, one of the most active members of the DBI community, explain the architecture of DBI and show how to write DBI-based programs. For the DBI expert, they cover the nuances and peculiarities of each individual database driver.