A materialized view is a database object that contains the results of a query. The FROM clause of the query can name tables, views, and other materialized views.
When you create a materialized view, Oracle Database creates one internal table and at least one index, and may create one view, all in the schema of the materialized view. Oracle Database uses these objects to maintain the materialized view data. You must have the privileges necessary to create these objects.
SQL> select OBJECT_NAME,OBJECT_TYPE,CREATED from dba_objects where OBJECT_NAME like 'XXAP%MV';
OBJECT_NAME OBJECT_TYPE CREATED
---------------------------------- ------------------- -------------------------------------------------------------------
XXAP_GL_BALANCES_MV TABLE 01-NOV-11
XXAP_GL_BALANCES_MV MATERIALIZED VIEW 01-NOV-11
XXAP_LIABILITY_BALANCES_MV TABLE 01-NOV-11
XXAP_LIABILITY_BALANCES_MV MATERIALIZED VIEW 01-NOV-11
The keyword SNAPSHOT is supported in place of MATERIALIZED VIEW for backward compatibility