Aliases and Duplicate in OBIEE

Difference between aliases and duplicate tables:

Alias Table	Duplicate Table
It’s a mirror image of the Parent Table	It’s a Copy of the Parent Table
We can't edit or modify Alias Table	We can edit/modify/delete columns in Duplicate table
It refers to physical table and created at physical layer of RPD	It doesn’t refer to physical table and created at all levels of RPD
It doesn’t create views.	It creates views using select statement.
Changes made in Parent Table is automatically reflected in Alias table	Changes made in Parent table are not reflected in Duplicate table
Used : When there is a need to avoid self-join or circular join	Used when there is a need to use few columns of Parent table.