Chapter 1, What Is a PostgreSQL Server?, introduces you to the PostgreSQL server and will set the tone for the rest of the book. It introduces you to the ways in which a PostgreSQL server is extendible, and shows you that it can be treated as a complete software development framework instead of just a database server.

Chapter 2, Server Programming Environments, elaborates that PostgreSQL is built to handle user needs, but more importantly, it is built not to change underneath users in the future. It will touch upon the environments and will highlight some of the important things to be kept in mind when programming on the server in PostgreSQL.

Chapter 3, Your First PL/pgSQL Function, builds the foundations by demonstrating how to write simple PL/pgSQL functions.

Chapter 4, Returning Structured Data, builds on the knowledge of writing PL/pgSQL functions and demonstrates how to write functions that return a set of values such as rows, arrays, and cursors.

Chapter 5, PL/pgSQL Trigger Functions, discusses how to write PL/pgSQL functions that are used to write trigger logic. It also discusses the various types of triggers available in PostgreSQL and the options that a database developer has when writing such functions.

Chapter 6, PostgreSQL Event Triggers, discusses PostgreSQL's event trigger functionality. Event triggers are fired when running a DDL operation on a table. This chapter discusses the various possibilities and options of creating event triggers and their limitations in PostgreSQL.

Chapter 7, Debugging PL/pgSQL, elaborates on how to debug PL/pgSQL's stored procedures and functions in PostgreSQL. This chapter explains how to install the debugger plugin and use the pgAdmin debugger console.

Chapter 8, Using Unrestricted Languages, explains the differences between restricted and unrestricted PostgreSQL languages. This chapter uses PL/Python as an example and demonstrates the examples of both restricted and unrestricted functions in PL/Python.

Chapter 9, Writing Advanced Functions in C, explains how to extend PostgreSQL by writing user-defined functions (UDFs) in C.

Chapter 10, Scaling Your Database with PL/Proxy, explains the use of a special programming language in PostgreSQL called PL/Proxy and how to use it in order to partition and shard your database.

Chapter 11, PL/Perl – Perl Procedural Language, discusses a popular PL language in PostgreSQL called PL/Perl. This chapter uses some simple examples to demonstrate how you can use Perl to write database functions.

Chapter 12, PL/Tcl – Tcl Procedural Language, discusses Tcl as a language of choice when writing database functions. It discusses the pros and cons of using Tcl in the database.

Chapter 13, Publishing Your Code as PostgreSQL Extensions, discusses how to package and distribute the PostgreSQL extensions. Well-packaged extensions can be easily distributed and installed by other users. This chapter also introduces you to the PostgreSQL Extension Network (PGXN) and shows you how to use it to get the extensions published by other developers.

Chapter 14, PostgreSQL as an Extensible RDBMS, discusses more extensibility options in PostgreSQL, such as creating new data types, operators, and index methods.

In order to follow this book, you need the following software:

This book is for moderate to advanced level PostgreSQL database professionals. To get a better understanding of this book, you should have a general experience in writing SQL, a basic idea of query tuning, and some coding experience in a language of your choice.

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "If any of the checks fail, you should do ROLLBACK instead of COMMIT."

A block of code is set as follows:

CREATE TABLE accounts(owner text, balance numeric, amount numeric);
INSERT INTO accounts VALUES ('Bob',100);
INSERT INTO accounts VALUES ('Mary',200);

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

CREATE OR REPLACE FUNCTION fibonacci_seq(num integer)
  RETURNS SETOF integer AS $$
DECLARE
  a int := 0;
  b int := 1;
BEGIN
  IF (num <= 0)
    THEN RETURN;
  END IF;

  RETURN NEXT a;
  LOOP
    EXIT WHEN num <= 1;
    RETURN NEXT b;

      num = num - 1;
      SELECT b, a + b INTO a, b;
  END LOOP;
END;
$$ LANGUAGE plpgsql;

Any command-line input or output is written as follows:

$ psql -c "SELECT 1 AS test"

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "Enter some values into the columns, as seen in the preceding screenshot, and click on the Debug button."

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