Managing tables

In this section, we will learn how to manage tables in the database.

PostgreSQL has three types of tables:

• Temporary tables: Very fast tables, visible only to the user who created them
• Unlogged tables: Very fast tables to be used as support tables common to all users
• Logged tables: Regular tables

We will now use the following steps to create a user table from scratch:

1. Create a new database using the following command:

forumdb=# create database forumdb2;
CREATE DATABASE

2. Execute the following command:

forumdb=# \c forumdb2
You are now connected to database "forumdb2" as user "postgres".

forumdb2=# CREATE TABLE users (
 pk int GENERATED ALWAYS AS IDENTITY
 , username text NOT NULL
 , gecos text
 , email text NOT NULL
 , PRIMARY KEY( pk )
 , UNIQUE ( username )
 );
CREATE TABLE

The CREATE TABLE command creates a new table. The command GENERATED AS IDENTITY, automatically assigns a unique value to a column.

3. Observe what was created on the database using the...