Oracle-GTTs

GTTS: Global Temporary Tables
Data stored in table to be referred during the session i.e. data in a temporary table is private to the session and purpose can be as follows:

1) Calculation
2) To maintain some data in temp state to process some operation

on commit delete rows
on commit preserve rows till session last

Oracle-Package-Benifits

The purpose of writing packages in oracle to implement the concept of modular methodology which explained as follows: 

1)Consolidate logical procedure and functional under one package 

2)There is way to define member variable in global and can be accessed with in package or outside packages 

3)The program units defined in package will be loaded at once in memory for processing and reduces context switching time

4)Program units can be make private

5)Package body can be re-compiled in isolation and will not invalidate dependencies 

5) Program units can be Overloaded