Data sources in reports are built differently than data sources in forms. As mentioned
earlier in this chapter, using multiple data sources in a form places all the data
sources as a list right under the Data Sources node. In reports, a Data Source also
has a subnode called Data Sources, where joined data sources can be placed.
This is because the Data Sources node in a report consists of a query and queries are
built in a tree style to visualize the joins better. In Chapter 5, Search For Data, we will
learn more about queries.