Prior to Oracle 18c , there is no difference between user and schema . It has been used interchangeably .
SQL Server has introduced the concept of "SCHEMA" only accounts quite a while ago.
Now , Oracle 18c ( aka 12c R2) has this new feature .
We can create a schema only account with the clause " no authentication". Once this schema gets created , the objects can be accessed by either proxy users , other users .
Prior to this , typically , I create a user with no "create session" privilege ; store only the persistent information in that user . Then there will be another user that does the data processing and the logic is exposed as an API.
With 18c and " no authentication" clause , it is easier from management/administration perspective.
Example shown below
SQL> create user sales no authentication ;
User created.
SQL> alter user sales quota unlimited on users;
User altered.
SQL> alter user sales default tablespace users;
User altered.
SQL> create table sales.employees ( empname char(50)) ;
Table created.
SQL> create user webappuser identified by Pa55w0rd ;
User created.
SQL> grant select , insert , update , delete on sales.employees to webappuser;
Grant succeeded.
SQL> grant create session to webappuser ;
Grant succeeded.
SQL> alter user webappuser default tablespace users;
User altered.
SQL> alter user webappuser quota unlimited on users;
User altered.
Now , login as webappuser .
SQL> insert into sales.employees values ('Zahir');
1 row created.
SQL> commit;
Commit complete.
SQL> show user
USER is "WEBAPPUSER"
SQL>
