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PostgreSQL 10 Administration Cookbook

You're reading from   PostgreSQL 10 Administration Cookbook Over 165 effective recipes for database management and maintenance in PostgreSQL 10

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Product type Paperback
Published in May 2018
Publisher Packt
ISBN-13 9781788474924
Length 576 pages
Edition 4th Edition
Languages
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Authors (2):
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Gianni Ciolli Gianni Ciolli
Author Profile Icon Gianni Ciolli
Gianni Ciolli
Simon Riggs Simon Riggs
Author Profile Icon Simon Riggs
Simon Riggs
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Toc

Table of Contents (14) Chapters Close

Preface 1. First Steps FREE CHAPTER 2. Exploring the Database 3. Configuration 4. Server Control 5. Tables and Data 6. Security 7. Database Administration 8. Monitoring and Diagnosis 9. Regular Maintenance 10. Performance and Concurrency 11. Backup and Recovery 12. Replication and Upgrades 13. Other Books You May Enjoy

Using psql variables

In the previous recipe, we have seen how to use the ON_ERROR_STOP variable. Here we show how to work with any variable, including user-defined ones.

Getting ready

As an example, we create a script that does some work on a given table. We will keep it simple, because we just want to show how variables work.

For instance, we might want to add a text column to a table, and then set it to a given value. So we write the following lines into a file called vartest.sql :

ALTER TABLE mytable ADD COLUMN mycol text;
UPDATE mytable SET mycol = 'myval';

The script can be run as follows:

psql -f vartest.sql

How...

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