Note: Install PostgreSQL 9.5 on Ubuntu 18.04

Since you can't mess with the production environment, there are times when you want to prepare a specific version of the DB environment in another environment. It is a memo for myself in such a case.

• Ubuntu18.04LTS
• PostgreSQL9.5

postgreSQL 9.5 installation

curl https://www.postgresql.org/media/keys/ACCC4CF8.asc | apt-key add -
echo "deb http://apt.postgresql.org/pub/repos/apt/ $(lsb_release -cs)-pgdg main" > /etc/apt/sources.list.d/pgdg.list
apt update
apt install postgresql-9.5

start postgreSQL

systemctl start [email protected]

Login

su postgres
psql -U

Database list display

# \l
                                   List of databases
    Name     |  Owner   | Encoding |   Collate   |    Ctype    |   Access privileges
-------------+----------+----------+-------------+-------------+-----------------------
 postgres    | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 |
 template0   | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 | =c/postgres          +
             |          |          |             |             | postgres=CTc/postgres
 template1   | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 | =c/postgres          +
             |          |          |             |             | postgres=CTc/postgres

Database creation

create database test

Create table

Set the pkey column as the primary key.

 create table test (pkey serial primary key, id integer);

Table list display

# \d
              List of relations
 Schema |     Name      |   Type   |  Owner
--------+---------------+----------+----------
 public | test          | table    | postgres
 public | test_pkey_seq | sequence | postgres
(2 rows)

When postgreSQL sets the primary key, the "test_pkey_seq" table is automatically created.

Table selection

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

Table setting display

# \d test
                          Table "public.test"
 Column |  Type   |                      Modifiers
--------+---------+-----------------------------------------------------
 pkey   | integer | not null default nextval('test_pkey_seq'::regclass)
 id     | integer |
Indexes:
    "test_pkey" PRIMARY KEY, btree (pkey)

Data insert

insert into test (id) values ('5'); 

Check the contents of the table

# select * from test;
 pkey | id
------+----
    1 |  5
(4 rows)

pkey is automatic.

Add column

# alter table test add column id2 integer;

I can't connect to postgreSQL from another console even though the command is correct.

psql -U postgres test
psql: FATAL:  Peer authentication failed for user "postgres"

cd /etc/postgresql/9.5/main
vim pg_hba.conf

pg_nba.Before changing conf

local   all             postgres                                peer

pg_nba.After changing conf

local   all             postgres                                md5  

Restart postgreSQL.

systemctrl restart postgresql

I was connected at another terminal. OK OK.