PL/SQL is Oracle's proprietary procedural language extension to SQL. It is used to create stored procedures and triggers inside Oracle databases. Using PL/SQL, a lot of application logic can be moved into the database, an approach with a number of advantages: Improved performance, because PL/SQL gets compiled right into the database server, uses native types and does not need to ship data across the network. Finer access control, as it becomes possible to explicitly specify how the database objects can be used and by whom. Better error detection and tracking of dependencies, because the code is not scattered among numerous middle-ware modules in host languages that cannot even check SQL syntax. PL/SQL itself is a rather old-fashioned language (nowhere as elegant as Perl) but its tight integration with SQL and the Oracle platform make it an easy-to-use and powerful tool for server-side programming.