Guide to create a linux user and grant read-only access for it for database.
1) Create a linux user and set password
sudo adduser read_access
Then enter your password for this user
2) Limit permission for the user (option)
Normally, this user only has root permission on it’s directory. (/home/read_access)
3) Set read-only role for this user to use Postgresql
psql -U postgres -d <your database>
After connected to psql console
CREATE USER read_access WITH PASSWORD '<your password>';
GRANT CONNECT ON DATABASE <your database> TO read_access;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO read_access;
GRANT SELECT ON ALL SEQUENCES IN SCHEMA public TO read_access;
ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT ON TABLES TO read_access;
ALTER USER read_access SET default_transaction_read_only = on;
4) Dump your database
PGPASSWORD="<your password>" pg_dump -Fc --no-acl --no-owner -h localhost -U read_access -d <your database> -t <your table> > mydb.dump
5) If you try to “change you will get this error”
ERROR: cannot execute INSERT in a read-only transaction