An alias is a logical pointer to an alternate table name. The purpose of an alias is to resolve loops in the paths of joins. In some cases more than one alias may be necessary for a given table.

Cheers

Sithu

Actually What happens in the back end (i.e) in database end while alias is performed whether it points to one table or too many table. How the performance will be in universe level.

Please help me by explaining with this concept correctly because i faced such question by interviewer.

An alias is identical to base table with different name. The data in alias is
exactly same as original table/but the different name tricks SQL into accepting
that we are using 2 different tables.

An alias breaks the loop by using the same table twice in the same query for
a different purpose.

Creation of alias tables is not much recommended in BO designer. Instead it
is recommended to delete the unnecessary joins that have n-n cardinality to
resolve loops.