Concept of Temporary Table  and Index-Organized  Table 

Tempaorary Table

Tempaorary Table is table contains  session-specific or transaction-specific data.And it is used for saving intermeditate results. It is Empty table when session or transaction begins.It will discard the data at end of the session or transation.

Benefits

• Eliminates the need to create and drop tables to store intermedia data.
  
• Improves performace of data transactions.
  
• Temporary table use temporary segments performance is increased significantly.
  

Index-Organized Table

Index-Organized Table is differs from ordinary table in that the data is held its associated index.When changing data  like adding new rows , updating rows and deleting rows result in updating only by index.

• Index-Organized tables provide faster key-based access to table data .
  
• The storage requiremnts are reduced because key columns are not duplicated.