Oracle allows you to do do that, but Oracle does not provide a built-in user or role exactly like that. Here are the steps you need:
1. Log in to Oracle with an account that has DBA privileges (like SYS or SYSTEM)
2. create user read_only identified by secret;
3. grant connect, create session to read_only;
4. Log in as the owner of the objects you want this new user to be able to read (select) from, and for each table or view do:
grant select on [table or view name] to read_only;
That will give you a user named "read_only" that will onlly be able to read from the objects you have authorized it to see (plus any default Oracle objects that include public "select" rights). You will have to use the full [schema_name].[table_name] (for example; scott.emp" for any tables that you want this read_only table to select from, unless you create private synonyms in the read_only schema or create public syn onyms as a DBA user. If you do either of those, your read_only user will be able to use statements like:
select * from emp;
instead of:
select * from scott.emp;
