Properties - Derive - Teradata Warehouse Miner

Teradata® Warehouse Miner™ User Guide - Volume 2ADS Generation

Teradata Warehouse Miner
Release Number
November 2018
English (United States)
Last Update
Product Category

If a Derive transformation is in use, a Derive tab is available on the Properties dialog. Click on Derive to access a variation of the Variable Creation input screen. It has been altered to initially contain a single variable consisting of the column that the Derive transformation is based upon. It has also been altered so that the input table cannot be changed and so that a new variable cannot be entered or the existing one deleted.

Special handling is given to aggregation functions if they appear in the user-defined expression. Any requested aggregation function is computed over the entire input table (limited by the Where clause, if specified as an expert option) in one of the global aggregate derived tables shared by the other transformation functions. The aggregation is then treated as a constant in the user-defined expression. Although the user-defined expression may include ordered analytical functions, it may not include an aggregate within an Ordered Analytical function.

Special handling is also given when specifying the default properties for a Derive transformation in the Default Properties dialog. A single variable called <default column> is initially provided. Wherever it appears in the expression created by the user, it will be replaced by the selected column that was used to define a specific Derive transformation. If more instances of <default column> are needed, the initially provided instance can be copied by dragging it with the control key held down. This makes the default Derive transformation behave like a template for a custom transformation.

After setting values/options on the Properties dialog, click OK to close the Properties dialog. Then continue specifying INPUT and OUTPUT parameters described in the following sections.