For good performance in oracle need tunning your database. Can use Build Index for the example :
Build Index :
BEGIN SYS.DBMS_STATS.GATHER_INDEX_STATS ( OwnName => 'DIARYCODING_DB' ,IndName => 'DIARY_REASON_PK' ,Estimate_Percent => 0 ,Degree => 4 ,No_Invalidate => FALSE); END;