we have several fact-tables which refer with different date-columns to a datehierachy. At the moment we need to implement for each date-column a separete date-table (including the Datehierarchy). This makes to model large and confusing.

Improvment: similar to multidimensional-cubes we want to implent just one datehierarchy which can refer to many date-column in several fact-tables. (at the moment we can just refer one active relation to another table)