Comparing relationship notation and multiple extract steps
When working with dependent objects in your Extract DataRaptor, you may need to retrieve records from a parent along with the corresponding values from child objects. There are two ways of getting this done. First, you can extract records from the parent object and each of your child objects, just like you would with any multi-object extract. Second, you can also use a trick called relationship notation, which is the equivalent of traversing relationships in SOQL. Relationship notation allows DataRaptors to use child-to-parent relationship queries, traversing the object relationships defined in your Salesforce org.
Note
Only child-to-parent relationship queries are supported in DataRaptors and not parent-to-child relationship queries. See the Relationship Queries documentation page (https://developer.salesforce.com/docs/atlas.en-us.248.0.soql_sosl.meta/soql_sosl/sforce_api_calls_soql_relationships.htm) for more information...