Large Number Support (Teradata Database)

Teradata Warehouse Miner User Guide - Volume 1Introduction and Profiling

Teradata Warehouse Miner
User Guide

The data types for Big Integers (BIGINT, containing up to about 20 digits) and Big Decimals (DECIMAL type with precision greater than 18, up to 38 digits), introduced in Teradata V2R6.2, are supported in Teradata Warehouse Miner in a limited manner. This is also true for the NUMBER data type introduced in Teradata 14.00, which may be used to store floating point or large decimal data and perform calculations with a guaranteed precision of 38 digits. NUMBER(*) and NUMBER(*,n) hold floating point values, and NUMBER(m) and NUMBER(m,n) store decimal values. With some limitations (NUMBER(*) and NUMBER(*,n) are displayed as floating point type with reduced precision), it is possible to view these large number types in the results data grid and to select them in the various Values wizards, as well as to view the appropriate type information in column selectors.

In general, big number columns may experience precision loss or graphing problems in Descriptive Statistics. ADS and Reorganization functions support the new types in most cases, but a warning is given about possible precision loss in the numeric transformations Rescale, Sigmoid and Z-Score. Though allowed with a warning, the big number types are not recommended for the analytic algorithms, and should be analyzed cautiously when using the Statistical Tests.

The following table summarizes the support for big numbers in various types of analyses.
Support for Big Numbers per Analysis
Analysis Big Number Support
Values Treats as a numeric type
Statistics Operates normally but gives a warning
Frequency Operates normally but use of big numbers as Statistics columns gives a warning
Histogram Operates normally but gives a warning
Adaptive Histogram Operates normally but gives a warning
Correlation Matrix Gives a warning
Overlap Supported
Scatter Plot Not recommended (gives a warning)
Data Explorer Operates normally but gives a warning
Text Field Analyzer Supported
Free Form SQL Big numbers may be selected and viewed
Variable Creation Supported
Variable Transformation Supported with a warning for Rescale, Sigmoid and Z-Score
Build ADS Supported
Refresh Not applicable
Reorganization analyses Supported
Association Supports big numbers as input columns
Analytic (other) algorithms Gives a warning, but caution recommended
Statistical tests Gives a warning but caution is recommended; not recommended where numeric input is required (e.g., F(2)way Parametric Test)

When entering a big decimal literal value, such as in the Variable Creation or Variable Transformation analysis, values may be entered either in the format expected by Teradata (i.e., with a period as the decimal separator) or in the format appropriate to the current locale. However, a number separator should not be used when the decimal separator is other than a period; only a decimal separator should be used.