You can use multiple lookups in a mapping specification. After you add a lookup, you can edit it.

You can perform a lookup on the following sources:

Flat file
Relational table
Logical data object
Reference table

When you add a lookup to a mapping specification, the lookup returns the result of lookup to the target column. You can configure the lookup to return a single row or multiple rows. You can edit the lookups that you add to a mapping specification to modify how lookups are used in the mapping specification.

You can perform the following tasks with a lookup:

Get a related value. Retrieve a value from the lookup based on a value in the source. For example, you can look up an employee ID and return the employee name.
Get multiple values. Retrieve multiple rows from a lookup. For example, you can look up a department cost center and return all the employees in a department.
Perform a calculation. Retrieve a value from a lookup and use it in a calculation. For example, you can look up a sales tax percentage, calculate a tax, and return the tax to a target column.