PostgreSQL 15 : Install2023/04/28 |
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Install PostgreSQL to configure database server.
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| [1] | Install and start PostgreSQL. |
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root@www:~# apt -y install postgresql-15
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| [2] | By default setting, it's possible to connect to PostgreSQL Server only from Localhost with [peer] authentication. Refer to the official site below about details of authentication methods. ⇒ https://www.postgresql.jp/document/10/html/auth-pg-hba-conf.html |
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# listen only localhost by default root@www:~# grep listen_addresses /etc/postgresql/15/main/postgresql.conf #listen_addresses = 'localhost' # what IP address(es) to listen on; # authentication methods by default root@www:~# grep -v -E "^#|^$" /etc/postgresql/15/main/pg_hba.conf local all postgres peer local all all peer host all all 127.0.0.1/32 scram-sha-256 host all all ::1/128 scram-sha-256 local replication all peer host replication all 127.0.0.1/32 scram-sha-256 host replication all ::1/128 scram-sha-256 |
| [3] | On [peer] authentication, it needs OS user and PostgreSQL user whose name are the same to connect to PostgreSQL Server. |
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# add an PostgreSQL user and his Database with PostgreSQL admin user root@www:~# su - postgres postgres@www:~$ createuser ubuntu postgres@www:~$ createdb testdb -O ubuntu
# show users and databases postgres@www:~$ psql -c "select usename from pg_user;"
usename ---------- postgres ubuntu (2 rows)postgres@www:~$ psql -l
List of databases
Name | Owner | Encoding | Collate | Ctype | ICU Locale | Locale Provider | Access privileges
-----------+----------+----------+---------+---------+------------+-----------------+-----------------------
postgres | postgres | UTF8 | C.UTF-8 | C.UTF-8 | | libc |
template0 | postgres | UTF8 | C.UTF-8 | C.UTF-8 | | libc | =c/postgres +
| | | | | | | postgres=CTc/postgres
template1 | postgres | UTF8 | C.UTF-8 | C.UTF-8 | | libc | =c/postgres +
| | | | | | | postgres=CTc/postgres
testdb | ubuntu | UTF8 | C.UTF-8 | C.UTF-8 | | libc |
(4 rows)
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| [4] | Try to connect to PostgreSQL Database with a user added above. |
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# connect to testdb ubuntu@www:~$ psql testdb psql (15.2 (Ubuntu 15.2-1)) Type "help" for help. # show user roles testdb=> \du List of roles Role name | Attributes | Member of -----------+------------------------------------------------------------+----------- postgres | Superuser, Create role, Create DB, Replication, Bypass RLS | {} ubuntu | | {} # show databases testdb=> \l List of databases Name | Owner | Encoding | Collate | Ctype | ICU Locale | Locale Provider | Access privileges -----------+----------+----------+---------+---------+------------+-----------------+----------------------- postgres | postgres | UTF8 | C.UTF-8 | C.UTF-8 | | libc | template0 | postgres | UTF8 | C.UTF-8 | C.UTF-8 | | libc | =c/postgres + | | | | | | | postgres=CTc/postgres template1 | postgres | UTF8 | C.UTF-8 | C.UTF-8 | | libc | =c/postgres + | | | | | | | postgres=CTc/postgres testdb | ubuntu | UTF8 | C.UTF-8 | C.UTF-8 | | libc | (4 rows) # create a test table testdb=> create table test_table (no int, name text); CREATE TABLE # show tables testdb=> \dt List of relations Schema | Name | Type | Owner --------+------------+-------+-------- public | test_table | table | ubuntu (1 row) # insert data to test table testdb=> insert into test_table (no,name) values (01,'Ubuntu'); INSERT 0 1 # confirm testdb=> select * from test_table; no | name ----+-------- 1 | Ubuntu (1 row) # remove test table testdb=> drop table test_table; DROP TABLE testdb=> \dt Did not find any relations. # exit testdb=> \q # remove testdb ubuntu@www:~$ dropdb testdb ubuntu@www:~$ psql -l
List of databases
Name | Owner | Encoding | Collate | Ctype | ICU Locale | Locale Provider | Access privileges
-----------+----------+----------+---------+---------+------------+-----------------+-----------------------
postgres | postgres | UTF8 | C.UTF-8 | C.UTF-8 | | libc |
template0 | postgres | UTF8 | C.UTF-8 | C.UTF-8 | | libc | =c/postgres +
| | | | | | | postgres=CTc/postgres
template1 | postgres | UTF8 | C.UTF-8 | C.UTF-8 | | libc | =c/postgres +
| | | | | | | postgres=CTc/postgres
(3 rows)
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