PostgreSQL

Common Commands

List of Databases :
psql -l
\? Help
\d ~= desc

\c <database> -- select database

\dt Show Tables
\dT list datatypes
\df list functions
\di list indexes
\dv list views


  \da [PATTERN]  list aggregate functions
  \db [PATTERN]  list tablespaces (add "+" for more detail)
  \dc [PATTERN]  list conversions
  \dC            list casts
  \dd [PATTERN]  show comment for object
  \dD [PATTERN]  list domains
  \df [PATTERN]  list functions (add "+" for more detail)
  \dg [PATTERN]  list groups
  \dn [PATTERN]  list schemas (add "+" for more detail)
  \do [NAME]     list operators
  \dl            list large objects, same as \lo_list
  \dp [PATTERN]  list table, view, and sequence access privileges
  \dT [PATTERN]  list data types (add "+" for more detail)
  \du [PATTERN]  list users
  \l             list all databases (add "+" for more detail)
  \z [PATTERN]   list table, view, and sequence access privileges (same as \dp)

Admin SQL

Create User

CREATE ROLE k2patel LOGIN PASSWORD 'test' VALID UNTIL 'infinity';

Create Table Space

CREATE TABLESPACE k2patel OWNER k2patel LOCATION '/var/lib/pgsql/k2patel';

Create Database

CREATE DATABASE k2patel WITH OWNER = k2patel ENCODING = 'UTF8' TABLESPACE = k2patel LC_COLLATE = 'en_US.UTF-8' LC_CTYPE = 'en_US.UTF-8' CONNECTION LIMIT = -1;

List Current Activity

select * from pg_stat_activity;

Change Pasword

ALTER USER postgres WITH ENCRYPTED PASSWORD 'password';

Read Only User

This only allow user to access database but can not write to it.

Important: Before you grant make sure you selected database else it could not work

CREATE ROLE carol;
ALTER ROLE carol WITH NOSUPERUSER INHERIT NOCREATEROLE NOCREATEDB LOGIN ENCRYPTED PASSWORD 'password';
GRANT SELECT ON ALL TABLES IN SCHEMA public TO carol;

Tip: If there is ERROR : pg_dump: The command was: LOCK SEQUENCE public.client_group IN ACCESS SHARE MODE See next Section

\dp public.client_group; # check permission
GRANT SELECT ON ALL SEQUENCES IN SCHEMA public TO backup;

Tip: Even you can use above commands to create backup user for specific database.

Getting Connection Information

select inet_server_addr();

Following is the available procedures / variable.

Name                Description
current_catalog         name of current database (called "catalog" in the SQL standard)
current_database()      name of current database
current_schema[()]      name of current schema
current_schemas(boolean)    names of schemas in search path, optionally including implicit schemas
current_user            user name of current execution context
current_query()         text of the currently executing query, as submitted by the client (might contain more than one statement)
pg_backend_pid()        Process ID of the server process attached to the current session
pg_listening_channels()     channel names that the session is currently listening on
inet_client_addr()      address of the remote connection
inet_client_port()      port of the remote connection
inet_server_addr()      address of the local connection
inet_server_port()      port of the local connection
pg_my_temp_schema()     OID of session's temporary schema, or 0 if none
pg_is_other_temp_schema(oid)    boolean is schema another session's temporary schema?
pg_postmaster_start_time()  server start time
pg_conf_load_time()     configuration load time
session_user            session user name
user                equivalent to current_user
version()           PostgreSQL version information