This manual is part of the official reference documentation for PostgreSQL 9.0. It documents the client and server interfaces to PostgreSQL: the C/C++ interface libpq, the embedded SQL/C compiler ECPG and the server-side languages PL/pgSQL, PL/Tcl, PL/Perl and PL/Python. Each chapter includes reference documentation and examples. In particular, the use of triggers, rules and views is described in detail. The PL/pgSQL chapter also includes a guide to porting Oracle PL/SQL functions to PostgreSQL. The other volumes of this series are Volume 1A ''The SQL Language'' (ISBN 978-1-9[zasłonięte]06966-1), Volume 1B, the ''SQL Command Reference'' (ISBN 978-1-9[zasłonięte]06966-8), and Volume 3, the ''Server Administration Guide'' (ISBN 978-1-9[zasłonięte]06966-2). For each copy of this manual sold 1 USD is donated to the PostgreSQL project by the publisher, Network Theory Ltd.