Is DBD competes with DBI or what?No. They collaborate and depend on each other. There is one DBI but there are many DBDs. There is one DBD for each kind of database (e.g. DBD::mysql for MySQL). DBI doesn't do much without a DBD and the DBDs do nothing at all without DBI. They need to be used together to do anything. The other thing you need is a database (like MySQL) unless you use one of the stand-alone DBDs that has its own database bundled with it (DBD::SQLite, DBD::Xbase, DBD::AnyData, etc.) or things like DBD::Excel which don't require an external database. There are lots of good tutorials on the web and books published. Try http://dbi.perl.org, or a google search for things like "DBI tutorial" or "DBI book".
thanks, -rkl
Or, if the above doesn't make sense, perhpas this will help:
Three DBDs for the open source kings under the sky, Seven for the japh-lords in their halls of stone, Nine for mortal hackers doomed to die, One for the Dark Lord on his Redmond throne. One DBI to rule them all, One DBI to find them, One DBI to bring them all and in their parameters, bind them.
-- Jeff
