2.1.2.5 Lookup Table Column Types

A Range Lookup column type is to be used for columns that is meant to store a range of value from a minimum value to a maximum value. The minimum and the maximum values are stored in two separate Lookup columns in a Lookup column pair. The logical condition that relates to this column pair of values is: Range Lookup Minimum value =< matching instrument data <= Range Lookup Maximum value.

Range Lookups require that your lookup data do not have overlapping ranges as that would lead to ambiguous lookup values. An Exact Match is a literal database join and is used for columns meant to store a single value that is to be related as: matching instrument data = Exact Match column value. Exact Match supports all instrument-level measures, attributes, and dimension members (numbers, dates, or strings).

A Hierarchy Match is to be used for columns that would store dimension leaf member values. A Hierarchy Match of a Lookup table Driver lets you to match on dimension member values from a source instrument table with any leaf member that belongs to a hierarchical rollup point of that leaf. Hierarchy matching supports only Key Processing dimensions.

Note:

The domains of DATE, CHAR, FLAG are to be included subsequently in the Source Column Selection drop-down to facilitate creation of Lookup Tables using columns belonging to these three domain types. This is a known issue and would be addressed in the future release.

A Lookup Table may contain one or multiple Return Columns. The Return columns are meant to hold the vaues that are expected to be returned in response to a match arrived with the source instrument table. The return values expected in the return columns are, in most cases, numeric values.

A Lookup table may contain any number of rows, each row having the values of the different column types used, including the return column types. A Lookup table does not hold a duplicate row.

The process to input user data into a Lookup table is to use the Lookup Table Data screen in the Lookup Table Driver module. For more information, see the Lookup Table Driver documentation. The following is a screenshot of the Lookup Table Data screen.

Figure 2-8 Lookup Table Data Screen