Oracle exports empty tables (tables that have never been used)

oracle11g default to Empty table is not assigned segment, so when using exp export oracle11g database, empty table will not export! 1, set the deferred_segment_creation parameter to false, whether it is an empty table or a non-controlled table, assign segment. In the Sqlplus command window, execute: SQL>Show parameter Deferred_segment_creationname TYPE VALUE------------------------------------ ----------- ------------------------------Deferred_segment_creation Boolean Truesql> AlterSystemSetDeferred_segment_creation=false2  ; System Alteredsql>Show parameter Deferred_segment_creationname TYPE VALUE------------------------------------ ----------- ------------------------------Deferred_segment_creation Boolean Falsesql>This value is set only after the newly added table, which has no effect on the previously established empty table! 2, using allocate extent to find empty table informationSelect *  fromUser_tableswhereNum_rows=0 orNum_rows is NULL; form a valid execution SQL statementSelect 'ALTER TABLE'||table_name||'allocate extent;'  fromUser_tableswhereNum_rows=0 orNum_rows is NULL; execute AS table ABCAlter TableABC allocate extent;

Oracle exports empty tables (tables that have never been used)