Databases Reference
In-Depth Information
Unlike the multiple hierarchical levels of objects in an enterprise, only
two hierarchical levels exist in a Time Variant data warehouse. The lowest
level presents each individual occurrence of an object: Halloween candy
and Holiday candy are individual occurrences of candy. An individual
object, therefore, has two hierarchical levels of the time variant occur-
rences: the individual instance of an object, which is represented by the
Instance_Key (i.e., Halloween candy, Holiday candy, Supplier A m ilk
from 2009 and Supplier B milk from 2010), and the universe of all occur-
rences of an object represented by the Entity_Key of the same object (i.e.,
all iterations of candy and all iterations of milk).
forms of tIme vArIANt mArket BAsket ANAlysIs
The forms of Time Variant Market Basket Analysis are the permutations
of Object (Driver and Correlation) and Key (Instance_ and Entity_). This
should sound very similar to the permutations of Object (Driver and
Correlation) and Key (Object_ and Hierarchy_) in Chapter 7, because
they are conceptually the same. The hierarchy between an Object_Key
and its hierarchical parent Hierarchy_Key is the same relationship as that
between an Instance_Key and its hierarchical parent Entity_Key.
• Instance Driver Object and Instance Correlation Object—his
form of Time Variant Market Basket Analysis will juxtapose each
occurrence of Driver Object (e.g., Halloween candy, Holiday candy,
Supplier A milk from 2009 and Supplier B milk from 2010) with each
occurrence of Correlation Object (e.g., Halloween candy, Holiday
candy, Supplier A milk from 2009 and Supplier B milk from 2010).
• Halloween candy juxtaposed with…
− Holiday Candy
− Supplier A milk from 2009
− Supplier B milk from 2010
• Holiday candy juxtaposed with…
− Halloween Candy
− Supplier A milk from 2009
− Supplier B milk from 2010
• Supplier A milk from 2009 juxtaposed with…
− Halloween Candy
