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PostgreSQL 9 Administration Cookbook - Second Edition
book

PostgreSQL 9 Administration Cookbook - Second Edition

by Simon Riggs, GIANNI CIOLLI, Hannu Krosing, Gabriele Bartolini
April 2015
Intermediate to advanced content levelIntermediate to advanced
504 pages
11h 41m
English
Packt Publishing
Content preview from PostgreSQL 9 Administration Cookbook - Second Edition

Changing the data type of a column

Thankfully, changing column data types is not an everyday task, but when we need to do it, we must know all the details so that we can perform the conversion on a production system without any errors.

Getting ready

Let's start with a simple example of a table, as follows:

postgres=# select * from birthday;

This gives the following output:

 name  |  dob   
-------+--------
 simon | 690926

(1 row)

The preceding table was created using this command:

CREATE TABLE birthday
( name       TEXT
, dob        INTEGER);

How to do it…

Let's say we want to change the dob column to another data type. Let's try with a simple example first, as follows:

postgres=# ALTER TABLE birthday
postgres-# ALTER COLUMN dob SET DATA TYPE text;
ALTER TABLE
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Publisher Resources

ISBN: 9781849519069Supplemental Content