$ su oracle
$ sqlplus / as sysdba

CREATE USER odb_test
IDENTIFIED BY odb_test
DEFAULT TABLESPACE users
TEMPORARY TABLESPACE temp;

GRANT
CREATE TABLE,
CREATE SEQUENCE,
CREATE TRIGGER,
CREATE SESSION,
UNLIMITED TABLESPACE TO odb_test;

=======

If you are getting "ORA-12516: TNS:listener could not find available
handler with matching protocol stack" (this seems to be the case with
10.2 XE), you will need to increase the number of connections/processes:

col name format A30
col value format A30
select name, value from v$parameter where name in ('processes','sessions');
alter system set processes=300 scope=spfile;
alter system set sessions=300 scope=spfile;

Then restart the database (via init.d).

=======

If running an OCI-based client under valgrind you get "ORA-12546: TNS:
permission denied", then you need to set the TWO_TASK environment
variable:

export TWO_TASK=<service name>

For example:

export TWO_TASK=xe