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

Conditional expressions


Conditional expressions allow developers to control the action of the function based on a defined criteria. The following is an example of using a CASE statement to control how a string is treated based on its value. If the value is null, or contains a zero length string, it is treated the same as null.

CREATE OR REPLACE FUNCTION format_us_full_name(

                             prefix text, firstname text, 

                             mi text, lastname text, 

                             suffix text)

  RETURNS text AS

$$

DECLARE

  fname_mi text;

  fmi_lname text;

  prefix_fmil text;

  pfmil_suffix text;

BEGIN

  fname_mi := CONCAT_WS(' ',
                                  CASE trim(firstname) 

                                    WHEN '' 

                                    THEN NULL 

                                    ELSE firstname 

                                  END, 

                                  CASE trim(mi) 

                       ...