To set up Lookup rules open the Tabular Tab of the Data Calculator window. If Lookup ports are available an additional Lookup column is displayed.
You must provide the following information for each lookup rule:
Key Expression — This is the value to search for in the first column of the lookup list. You enter the key expression (for example IN.PR_ID) as the Transformation Rule.
Return Value — Since lookup lists can have more than one return value columns you have to specify which value to return, if the key has been found. This is done by selecting the associated port attribute from the pop-up menu on the Lookup column (for example LOOKUP1>>LOOKUP1.PR_NAME).
Although the return values are selected and displayed
by name, the lookup internally uses the column number. This means
you will need to review your lookup rules whenever the lookup port
structure is modified, especially after adding or removing attributes.
The key column is always returned as Unicode.
Output Variable — The Lookup return value is assigned to this variable. You can select a variable from the pop-up menu on the Output Port column (for example, OUT>>OUT.PR_NAME).
Default Expression (optional) — A Lookup will return Null if the given key value is not found. To return a different default value you can enter an expression in the Lookup Options window (for example, “key not found”).
