In Postgres and similarly in other SQL databases users of a database have a certain level of access depending on the privileges set for the particular user. The reason you would want to have multiple users in a postgres table is to create different levels of access for each particular user.
To get a list of all users of a postgres database you will first need to access the database server using psql and then you can run the command
\du, which will give you a list of users and the roles / privileges.
The different privileges that exist in postgres include: SELECT, INSERT, UPDATE, DELETE, TRUNCATE, REFERENCES, TRIGGER, CREATE, CONNECT, TEMPORARY, EXECUTE, and USAGE.
To add a role for a user you can use the GRANT keyword:
GRANT UPDATE ON reports TO ted.lasso;
To remove a role from a user you can use the REVOKE keyword:
REVOKE UPDATE ON reports FROM ted.lasso;
Adding all privileges to a user defeats the purpose of creating a new user since the table owner aka Superuser will have the ability to do so. To change the owner of the table, you can use the following command:
ALTER DATABASE dev_decks_dev OWNER TO ted.lasso;
To create a new user for an existing database in postgres use the CREATE USER command like so:
CREATE USER new_user;
Do databases make you dancey? Maybe you’d enjoy dancing to the beat of postgres stored procedures.