General Differences between DB2 and Oracle

• A DB2-Instance can serve several independent  DB2-databases
• One DB2-Instance is referenced by an OS-User with similar name
• The home directory of the OS-User is the instance home directory
• DB2 does not know about user administration
• DB2 user are authenticated by Operating System Users or
  Directory Services e.q. NIS, LDAP,AD
• There is one Alertlog per Instance called db2diag.log
• A DB2-database is started on demand by the first connection
• there is no ROLLBACK-/UNDO-Management in DB2
  • Oracle:   Multi Version Read Consistency
  • DB2:       ANSI standard Isolation levels
                   Repeatable Read, Read Stability, Cursor Stability
                   and Uncommitted Read (Dirty Read)

  Further Information about: DB2 Online Documentation