Value based hierarchies and Period dimension should only contain 2 monthl

Question

Hi,
Can anyone tell me what is value based hierarchies. And also can anyone let me know to filter the records in AWm because in Period dimension should only contain 2 monthly values (Oct. 2008 ( 200810) and Sep. 2008 ( 200809)) it is urgent.
Thanks
vel

Answer 1

The following definition of a value hierarchy comes from the OLAP Developers guide
"A hierarchy defined only by the parent-child relationships among dimension members. The dimension members at a particular distance from the base level do not form a meaningful group for analysis, so the levels are not named. For example, an employee dimension might have a parent-child relation that identifies each employee's supervisor. However, levels that group together first-, second-, and third-level supervisors and so forth may not be meaningful for analysis."
Typically this means that the source table has two columns, VALUE and PARENT, where PARENT has a (logical) foreign key relationship to VALUE. An example may be EMPLOYEE, MANAGER, where MANAGERs are also EMPLOYEEs.
The simplest way to restrict the values loaded into the AW is to define a SQL view over the source table with an appropriate WHERE condition. You then use AWM to map the dimension to your new view. E.g.
CREATE OR REPLACE VIEW RESTRICTED_TIME AS
SELECT *
FROM TIME
WHERE MONTH IN (200810, 200809)