---
layout: post
status: publish
published: true
title: 'PostgreSQL 101'
author:
  display_name: 'sipp11'
date: '2013-10-26'
categories:
- database
tags: postgresql 101
---

I found that PostgreSQL works differently to MySQL. PostgreSQL will accept command from both command shell ($) and PostgreSQL shell (postgres=#). When you create database, drop database, you can do from command shell: 

    $ createdb <database-name> -E UTF8
    $ dropdb <database-name>

while [charset support listed here](http://www.postgresql.org/docs/8.4/static/multibyte.html#MULTIBYTE-CHARSET-SUPPORTED). or you can create database inside postgres shell.

    $ psql
    postgres=# create database <database-name>
    postgres=# drop database <database-name>

To do some basic query, it's pretty like MySQL. However, it's vastly different when it comes to list/describe

    postgres=# \l  # show databases
    postgres=# \connect <database-name>  # use database
    <database-name>=# \d  # show tables
    <database-name>=# \d <table-name>  # show columns
    <database-name>=# \d+ <table-name>  # describe table

Configure for remote connection

### Server side

Edit `/etc/postgres/x.x/main/postgresql.conf`

    listen_addresses = '*'

Add line to `/etc/postgres/x.x/main/pg_hba.conf`

    host  all  all  0.0.0.0/0  md5

or you could do things like `192.168.1.1/24` if you want to limit to your subnet.

Creating remote user isn't anything different from what local user is:

    $ psql template1
    template1=# create user <user-name> with password '<your-password>';
    template1=# \connect <database-name>;
    <database-name>=> GRANT USAGE ON SCHEMA public to <user-name>;
    <database-name>=> GRANT SELECT ON ALL TABLES IN SCHEMA public TO <user-name>;
    <database-name>=> GRANT UPDATE ON ALL TABLES IN SCHEMA public TO <user-name>;
    <database-name>=> GRANT ALL ON ALL TABLES IN SCHEMA public TO <user-name>;
    <database-name>=> ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT ON TABLES TO <user-name>;
    <database-name>=> GRANT USAGE, SELECT ON SEQUENCE <table_name>_id_seq TO <user-name>;
    <database-name>=> GRANT USAGE, SELECT ON ALL SEQUENCES IN SCHEMA <schema_name> TO <user-name>;
    <database-name>=> \q

### Client side

Pretty much like MySQL

    $ psql -h <postgres-server> -d <database-name> -U <user-name>

If you don't have postgresql client yet

    # apt-get install postgresql-client-x.x

while x.x means version, e.g. `postgresql-client-9.1`