An Alias table is a physical table with the type of Alias. It is a reference to a physical table, and inherits all its column definitions and some properties from the physical table. A logical table source shows how the logical objects are mapped to the physical layer and can be mapped to physical tables, stored procedures and select statements. An alias table can be a reference to any of these logical table source types.
Alias Tables can be an important part of designing a physical layer. The following is a list of the main reasons to create an alias table
To reuse an existing table more than once in your physical layer (without having to import it several times)
To set up multiple alias tables, each with different keys, names, or joins
To help you design sophisticated star or snowflake structures in the business model layer. Alias tables are critical in the process of converting ER Schems to Dimensional Sachems.