The data view function in the Centerbase PC version allows users to set what fields are available when searching, importing, etc. in Centerbase. There are three sections to the Data View page: Item Type, Fields, and Preview.
First select the item you are searching from in the drop-down menu. All available lookup fields on that item appear below followed by linked items (in the square brackets). Selecting the main item will show the fields available on that item in the Fields section. Fields can be shown by checking the checkbox next to the field or hidden by unchecking.
In the above case, if I wanted to find contacts where the client had an email address while searching, I would need to go to the Contact, then the Client lookup and make sure the Email address was selected. The added field will appear in green in the Preview pane with the following format: LookupField.FieldonLookup.