Databases Reference
In-Depth Information
market Basket Analysis in a time variant
context at a high level
The Driver Objects and Correlation Objects of Market Basket Analysis are
dimensions. Typically we think of them as products in a shopping cart,
services in a work order, or menu items in a dinner. However, from the
broad perspective of Market Basket Analysis, they are dimensions. The
Time Variant Solution Design embeds two expressions of dimensions in
a Fact table. The Type 1 time variant expression of a dimension in a Fact
table is the Entity Key that joins to a Type 1 dimension table. The Type 2
time variant expression of a dimension in a Fact table is the Instance Key
that joins to a Type 2 dimension table.
A Driver Object can be an Entity Key or an Instance Key. A
Correlation Object can also be an Entity Key or an Instance Key. When
the Driver Object and Correlation Objects are Entity Keys, the Market
Basket Analysis considers both entities without any time variant con-
text. When the Driver Object and Correlation Object are Instance
Keys, the Market Basket Analysis considers both entities in their time
variant contexts.
The time variant contexts of the Driver and Correlation Objects can
juxtapose each other. When the Driver Object is an Instance Key and the
Correlation Object is an Entity Key, the Market Basket Analysis considers
each individual occurrence of the Driver Object against the whole uni-
verse of occurrences of the Correlation Object. When the Driver Object is
an Entity Key and the Correlation Object is an Instance Key, the Market
Basket Analysis considers the whole universe of occurrences of the Driver
Object against each individual occurrence of the Correlation Object.
elemeNts of tIme vArIANt
mArket BAsket ANAlysIs
We divulged the plot, including the big finish wherein we juxtapose the
time variant contexts of Itemsets. Now that all the secrets are on the table,
the first order of business is to define the elements of the Market Basket
Analysis. Chapter 5 deined the Market Basket Solution in terms of an
Itemset and Objects. The Itemset and Objects, therefore, are the elements
that must be defined in terms of the Time Variant Solution Design.
