the concept of oracle profile

use the create profile statement to create the profile which a set of limits on database resources
if you assign the profile to the use ,the use can not exceed these limits

Setting Profile Resource Limits: Example The following statement creates the profile app_user:

CREATE PROFILE app_user LIMIT
   SESSIONS_PER_USER          UNLIMITED
   CPU_PER_SESSION            UNLIMITED
   CPU_PER_CALL               3000
   CONNECT_TIME               45
   LOGICAL_READS_PER_SESSION  DEFAULT
   LOGICAL_READS_PER_CALL     1000
   PRIVATE_SGA                15K
   COMPOSITE_LIMIT            5000000;