Using the cascading lookup pattern

Typically, the structure and the semantics of a data flow source correspond to the data model used in the source data store; this structure, or the semantics used to represent data in the source system, might not be aligned with the structure or the semantics of the destination system.

For instance, the client entity in the source system might be represented by a single set, but the data warehouse might have to distinguish between a client, who is a person, and a client that represents a company. To correctly interpret the source data, you would need appropriate logic in the data flow to differentiate between source rows representing persons, and source rows representing companies, before loading the data correctly into the data destination data store.

How to do it...

1. In SSDT, open the AdventureWorksETL.sln solution located in the C:\SSIS2016Cookbook\Chapter06\Starter\AdventureWorksETL\ folder.
2. Make sure that the CascadingLookup.dtsx SSIS package is open, locate...