Compare Schemas or Tables ?

In Oracle 11g ,  a new package called DBMS_COMPARISON  lets  you compare data between  2 objects.  So now , you don’t have to write and test your home grown scripts.  DBMS_COMPARISON is provided mainly to detect or monitor data inconsistencies between database objects in  streams or GoldenGate. environment  This package lets you compare and converge data   for tables , materialized views , table synonyms and views (single table view only).

Once the comparison of database object is complete, you can get data inconsistencies report from data dictionary views like  DBA_COMPARISON, DBA_COMPARISON_COLUMNS,DBA_COMPARISON_SCAN, DBA_COMPARISON_SCAN_SUMMARY, DBA_COMPARISON_SCAN_VALUES and DBA_COMPARISON_ROW_DIF

Refer to Oracle Documentation for more information : http://download.oracle.com/docs/cd/B28359_01/appdev.111/b28419/d_comparison.htm