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

Running queries and calling PostgreSQL functions


Our next stop is running SQL queries inside the database. When you want to run a query against the database, you need to use something called Server Programming Interface (or SPI for short). SPI gives programmer the ability to run SQL queries via a set of interface functions for using PostgreSQLs parser, planner, and executor.

Note

If the SQL you are running via SPI fails, the control is not returned to the caller, but instead the system reverts to a clean state via internal mechanisms for ROLLBACK. It is possible to catch SQL errors by establishing a sub-transaction around your calls. It is a bit involved process not yet officially declared "stable" and thus Therefore, it not present in the documentation on C extensions. If you need it, one good place to look at would be source code for various pluggable languages (pl/python, pl/proxy, …) which do it and are likely to be maintained in good order if the interface changes.

In PL/Python source...