Specifying Transformation Instructions for an Attribute

A transformation list is defined as a table of transformation records. Each record (transform_rec) specifies the transformation instructions for an attribute.

TYPE transform_rec IS RECORD (
    attribute_name      VARCHAR2(30),
    attribute_subname   VARCHAR2(4000),
    expression          EXPRESSION_REC,
    reverse_expression  EXPRESSION_REC,
    attribute_spec      VARCHAR2(4000));

The fields in a transformation record are described in Table 4-2.

Table 4-2 Fields in a Transformation Record for an Attribute

Field	Description
`attribute_name` and `attribute_subname`	These fields identify the attribute, as described in "Scoping of Model Attribute Name"
`expression`	A SQL expression for transforming the attribute. For example, this expression transforms the age attribute into two categories: child and adult:[0,19) for 'child' and [19,) for adult CASE WHEN age < 19 THEN 'child' ELSE 'adult' Expression and reverse expressions are stored in `expression_rec` objects. See "Expression Records" for details.
`reverse_expression`	A SQL expression for reversing the transformation. For example, this expression reverses the transformation of the age attribute: DECODE(age,'child','(-Inf,19)','[19,Inf)')
`attribute_spec`	Specifies special treatment for the attribute. The `attribute_spec` field can be null or it can have one or more of these values: `FORCE_IN` — For GLM, forces the inclusion of the attribute in the model build when the `ftr_selection_enable` setting is enabled. (`ftr_selection_enable` is disabled by default.) If the model is not using GLM, this value has no effect. `FORCE_IN` cannot be specified for nested attributes or text. `NOPREP` — When ADP is on, prevents automatic transformation of the attribute. If ADP is not on, this value has no effect. You can specify `NOPREP` for a nested attribute, but not for an individual subname (row) in the nested attribute. `TEXT` — Indicates that the attribute contains unstructured text. ADP has no effect on this setting. `TEXT` may optionally include subsettings `POLICY_NAME`, `TOKEN_TYPE`, and `MAX_FEATURES`. See Example 4-1 and Example 4-2.