by Graham Williams
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GNU/Linux Desktop Survival Guide
by Graham Williams |
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PostgreSQL | 
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20200819 The PostgreSQL database is simple to install and test on a local machine. Below we install the software, create a database user (role) having the same username as the Linux user on the host system and grant the user superuser privileges. We also create a default database for that user.
$ wajig install postgresql $ sudo -u postgres createuser --interactive Enter name of role to add: kayon Shall the new role be a superuser? (y/n) y $ createdb kayon |
We can then start the database client with the psql command. Here we illustrated the creation of a new table and populate it from a csv file.
$ psql
sql (12.2 (Ubuntu 12.2-4))
Type "help" for help.
kayon=# CREATE TABLE iris(
sepal_length numeric,
sepal_width numeric,
petal_length numeric,
petal_width numeric,
species text);
CREATE TABLE
kayon-# \d
List of relations
Schema | Name | Type | Owner
--------+------+-------+-------
public | iris | table | kayon
(1 row)
kayon=# COPY iris FROM '/home/kayon/iris.csv' WITH (FORMAT csv, HEADER true);
COPY 150
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We can then query the database to check it has been properly populated.
kayon=# SELECT * FROM iris LIMIT 5;
sepal_length | sepal_width | petal_length | petal_width | species
--------------+-------------+--------------+-------------+---------
5.1 | 3.5 | 1.4 | 0.2 | setosa
4.9 | 3.0 | 1.4 | 0.2 | setosa
4.7 | 3.2 | 1.3 | 0.2 | setosa
4.6 | 3.1 | 1.5 | 0.2 | setosa
5.0 | 3.6 | 1.4 | 0.2 | setosa
(5 rows)
kayon=# \q
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