In this chapter, you've seen that PL/pgSQL provides a way for you to execute procedural code on the server. PL/pgSQL is not the only procedural language that you can use for server-side programming. The standard PostgreSQL distribution includes PL/perl, PL/python, and PL/tcl. You can also add functionality to the server using the Server Programming Interface. For more information on these features, refer to the PostgreSQL Programmer's Guide.
The next several chapters will describe the client-side programming interfaces included with PostgreSQL.