Databases Reference
In-Depth Information
The Market Basket Query provides all the elements of Market Basket
Analysis—Itemset, Driver Object, and Correlation Object. The Market
Basket Query is used to populate the table that will be used for analysis.
The good news about that development is that the recursive Market Basket
Query, which performs the heavy lifting in Market Basket Analysis, is per-
formed only once for each Itemset and under controlled and optimized
conditions. However, before we discuss the output from the Market Basket
Query, we need to understand the underlying logic that provides the ele-
ments of Market Basket Analysis.
Itemset
The Itemset_Key value that was included in the Market Basket Table is
preserved, as shown in Figure 5.3, without modification in the Market
Basket Query.
The Itemset_Key is the linchpin around which all this Market Basket
Solution Design revolves. The Itemset_Key must be identical for all rows
representing a transaction. The Itemset_Key must be unique to each and
every transaction such that each and every Itemset has its own unique
Itemset_Key. If two transactions share the same Itemset_Key, they will
be perceived to be the same transaction by the Market Basket Analysis. If
rows within a single transaction do not have the same Itemset_Key, they
will be perceived to belong to separate transactions by the Market Basket
Analysis. So, the success or failure of the Market Basket Solution Design
rests first on the integrity of the Itemset_Key.
Driver object
The Driver Object is represented by the columns that begin with DRIVER_,
as shown in Figure 5.4.
The DRIVER_OBJECT_KEY identifies the object that performs the
function of a Driver Object. In the context of the Market Basket Scope
Statement, the DRIVER_OBJECT_KEY refers to “When Driver Object A
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fIGure 5.3
Itemset.
