Book Image

PostgreSQL Server Programming

Book Image

PostgreSQL Server Programming

Overview of this book

Learn how to work with PostgreSQL as if you spent the last decade working on it. PostgreSQL is capable of providing you with all of the options that you have in your favourite development language and then extending that right on to the database server. With this knowledge in hand, you will be able to respond to the current demand for advanced PostgreSQL skills in a lucrative and booming market."PostgreSQL Server Programming" will show you that PostgreSQL is so much more than a database server. In fact, it could even be seen as an application development framework, with the added bonuses of transaction support, massive data storage, journaling, recovery and a host of other features that the PostgreSQL engine provides. This book will take you from learning the basic parts of a PostgreSQL function, then writing them in languages other than the built-in PL/PgSQL. You will see how to create libraries of useful code, group them into even more useful components, and distribute them to the community. You will see how to extract data from a multitude of foreign data sources, and then extend PostgreSQL to do it natively. And you can do all of this in a nifty debugging interface that will allow you to do it efficiently and with reliability.
Table of Contents (17 chapters)
PostgreSQL Server Programming
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Preface
Index

Why untrusted?


PostgreSQL's ability to use an untrusted language is a powerful way to perform some nontraditional things from database functions. Creating these functions in a PL is an order of magnitude smaller task than writing an extension function in C. For example, a function to look up a hostname for an IP address is only a few lines in PL/Pythonu:

CREATE FUNCTION gethostbyname(hostname text) 
  RETURNS inet
AS $$
  import socket
  return socket.gethostbyname(hostname)
$$ LANGUAGE plpythonu SECURITY DEFINER;

You can test it immediately after creating the function by using psql:

hannu=# select gethostbyname('www.postgresql.org');
 gethostbyname  
----------------
 98.129.198.126
(1 row)

Creating the same function in the most untrusted language, C, involves writing tens of lines of boilerplate code, worrying about memory leaks, and all the other problems coming from writing code in a low-level language. While we will look at extending PostgreSQL in C in the next chapter, I recommend prototyping...