What are Alias Tables and It's significance in OBIEE Physical Layer

An Alias Table or Alias in OBIEE is a physical table which references to a different physical OLAP/OLTP table as it's source.

Alias tables are often used for Repository development over Physical tables as they have the following properties,

1. Enables reuse of a physical table.
2. Avoids circular joins that can form when importing OLTP source tables.
3. Create self joins between tables, for eg: Manager is also an Employee.
4. Enables to easily identify source tables and adhere to data warehousing naming standards.
5. Makes physical query generated easier to understand.
6. Can override source table's caching properties like Cacheable, Cache never expires and cache persistence time. 

Alias Tables in OBIEE 11g - Example.