Advantages of using Alias Table in OBIEE

1. OBIEE does not support Circular join in BMM layer, we can overcome this problem by creating alias table for one of the table in that circular join.
2. You can create a join relationship which is different than the actual foreign key relationship in the database. This helps in defining relationships to meet business model criteria.
3. OBIEE does not support self-join,we can overcome from this problem by creating alias table.
4. Aliases can function in numerous ways to define business model.                                                                                               Example: A table can act both as dimension and fact using aliases.
5. If a fact table is having relationship with dimension table on more than one key, then we can create aliases for the dimension table, then we can join fact table to these alias tables on different keys.                                                               Example: Consider, there is an sales table, it has two columns in that, namely, Order_Date and Shipping_Date, both columns have to be joined to the Time dimension. In such a situation we can create alias for the Time dimension, like Order_Date_Dim and Shipping_Date_Dim. Now join the sales table to these tables on different keys. 
6. You can rename aliases to make physical and business model easier to understand.