The STACK Interface

The STACK interface creates transformation records from a table of transformation instructions and adds them to a transformation list.

The STACK interface specifies that all or some of the attributes of a given type should be transformed in the same way. For example, STACK_BIN_CAT appends binning instructions for categorical attributes to a transformation list. The STACK interface consists of three steps:

1. A CREATE procedure creates a transformation definition table. For example, CREATE_BIN_CAT creates a table to hold categorical binning instructions. The table has columns for storing the name of the attribute, the value of the attribute, and the bin assignment for the value.

2. An INSERT procedure computes the bin boundaries for one or more attributes and populates the definition table. For example, INSERT_BIN_CAT_FREQ performs frequency-based binning on some or all of the categorical attributes in the data source and populates a table created by CREATE_BIN_CAT.

3. A STACK procedure creates transformation records from the information in the definition table and appends the transformation records to a transformation list. For example, STACK_BIN_CAT creates transformation records for the information stored in a categorical binning definition table and appends the transformation records to a transformation list.