Applying rule expressions on columns to transform data

Use rule expressions created in IBM® InfoSphere® DataStage® and QualityStage to transform your data.

About this task

The rule expressions that transform the data are validated automatically by IBM InfoSphere FastTrack. You can use only the IBM InfoSphere DataStage and QualityStage rule expression. A rule expression is a relationship between a set of input data values and a set of result values.

Rule expressions that you apply in the mapping specification become rule expressions in the job. If you specify a nonvalid rule expression, the job will not compile, and you or a job developer will need to correct the rule expression later.

If you specify a nonvalid rule expression, a warning symbol and a message are displayed in the Validation view. The warning symbol is also displayed on the transformation cell in the mapping specification. The expression editor shows nonvalid expressions in red, and valid expressions in green or normal type.

Procedure

  1. In the table in the Mapping Editor, click the expander icon to the right of the Transformation column:
    The expander icon to the right of the Transformation column.
    The Rule Expression column is displayed.
    The column expands and the Rule expression column is displayed. This editor provides space for adding multi-line rule expressions. If you enable validation, there is real-time syntax validation on each rule expression that you specify.
  2. Type a rule expression in the Rule Expession column next to the column to which the rule expression applies. You can also type a rule expression in the expression editor that is part of the properties section below the mapping specification.
  3. Click Save. Alternately, you can specify the transformation expression in the lower part of the screen in the Transformation tab. In the Rule Expression field, you can use the auto-complete function by pressing Ctrl+Space. To view a more specific list of transformation expressions or fields, type the first letters of the transformation rule or field that you want, then press Ctrl+Space.