In Oracle 11g release 2, there are new feature to save disk spaces. There is a new database parameter in Oracle Database 11gR2, DEFERRED_SEGMENT_CREATION. Initially this parameter is set to TRUE. This parameter affect the export utility when exporting schema. The problem is that empty tables will not get exported by conventional export utility. For Export using Data Pump there is no problem with empty tables.
To disable this feature, you need to change the parameter to false:
SQL> alter system set DEFERRED_SEGMENT_CREATION=FALSE scope=both;
Then you need to move the tablespace of the empty tables or recreate the tables, so that Oracle will recognize the new created segment.
