Postgres：创建一个角色并使用 psql -U 角色登录

Question

Code:

postgres=# create role hello;
CREATE ROLE
postgres=# \du
                             List of roles
 Role name |                   Attributes                   | Member of
-----------+------------------------------------------------+-----------
 hello     | Cannot login                                   | {}
 postgres  | Superuser, Create role, Create DB, Replication | {}

postgres=# ALTER ROLE hello WITH LOGIN;
ALTER ROLE
postgres=# ALTER ROLE hello WITH CREATEDB;
ALTER ROLE
postgres=# \du
                             List of roles
 Role name |                   Attributes                   | Member of
-----------+------------------------------------------------+-----------
 hello     | Create DB                                      | {}
 postgres  | Superuser, Create role, Create DB, Replication | {}

postgres=# ALTER ROLE hello WITH PASSWORD '123';
ALTER ROLE
postgres=# \q
-bash-4.2$ logout
[root@host test_user]# psql -U hello
Password for user hello:
psql: FATAL:  database "hello" does not exist

I am trying to create a role named hello in Postgres with CREATE ROLE and changed it's permission for logging in and created database. However, when I try to login with -U it shows me the above. Is my understanding wrong here for -U ?

Answer 1

By default, another assumption that the Postgres authentication system makes is that there will be an database with the same name as the role being used to login, which the role has access to.

See here: link for more info.

After creating the database, you can then do:

sudo -u hello psql

to log in to the shell automatically.

Answer 2

so i ran into a similar issue, Basically what postgres is expecting is a database that you want to choose,

And when you run the command psql -U hello

It is assuming that you are trying to access hello database, But by default only postgres db is created . Try this command instead psql -U hello postgres