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

Variables passed to the PL/pgSQL TRIGGER function


The following is a complete list of variables available to a trigger function written in PL/pgSQL:

OLD, NEW

RECORD

before and after images of the row the trigger is called on. OLD is unassigned for INSERT and NEW is unassigned for DELETE.

Both are UNASSIGNED in statement-level triggers.

TG_NAME

name

The name of the trigger (this and following from the trigger definition).

TG_WHEN

text

One of BEFORE, AFTER, or INSTEAD OF.

TG_LEVEL

text

ROW or STATEMENT.

TG_OP

text

One of INSERT, UPDATE, DELETE, or TRUNCATE.

TG_RELID

oid

OID of the table the trigger is created on.

TG_TABLE_NAME

name

The name of the table (old spelling TG_RELNAME is deprecated but still available).

TG_TABLE_SCHEMA

name

The schema name of the table.

TG_NARGS, TG_ARGV[]

Int, text[]

Number of arguments and the array of the arguments from trigger definition.