Building Lookup Rules

Set up the lookup rules in the Data Calculator window.

Click the Tabular tab. If lookup ports are available, an additional Lookup column appears.

For each lookup rule, provide:

Key Expression – is the value to search for in the first column of the lookup list. Enter the key expression (for example IN.PR_ID) as a transformation rule.
Return Value – since lookup lists can have more than one return value column, you must specify which value to return, if the key is found. Select the associated port attribute from the pop-up menu on the Lookup column. For example: LOOKUP1>>LOOKUP1.PR_NAME.

Note:
Although return values are selected and displayed by name, the lookup internally uses the column number. This means you must review your lookup rules whenever the lookup port structure is modified, especially after you have added or removed attributes.
Output Variable – the lookup return value is assigned to this variable. You can select a variable from the Output Port column (for example, OUT>>OUT.PR_NAME).
(Optional) Default Expression – a lookup returns null if the given key value is not found. To return a different default value, enter an expression in the Lookup Options window. To open the Lookup Option window, click the icon in the Lookup column in the Transformation Rules and Current Output Record pane.