PostgreSQL 怎样给一个用户授予只读角色

postgresql 设置只读用户
`
CREATE USER readonly WITH ENCRYPTED PASSWORD 'ropass';
alter user readonly set default_transaction_read_only=on;
GRANT USAGE ON SCHEMA public to readonly;
ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT ON TABLES TO readonly;
-- repeat code below for each database:
GRANT CONNECT ON DATABASE foo to readonly;
\c foo
GRANT USAGE ON SCHEMA public to readonly;
GRANT SELECT ON ALL SEQUENCES IN SCHEMA public TO readonly;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO readonly;
`