Every user interface control has to get data from somewhere, and in Iron Speed Designer applications, that somewhere is a data source.  In a nutshell, a data source is an array of records.  Those records frequently are the result of an SQL query, but can be from other sources as well.  For example, the data source for a table control is a business class which returns and array of records to populate a table.

All data sources can be modified using the Query Wizard in the Data Sources tab.

The Finish step previews the SQL query to be created.