Child Data Link
That property allows specifying the child data link to be used to edit a Graph or to feed a Sub-Report or a Text/Query object or a Cross-Table or a Cube in a report.
New Feature in version 4.10: please note that if the graph is fed by data from the current report then the parent and child fields will not be used.
Use that button to display the available field names corresponding to
the query on which the Graph is based, specified in the Data Source property for the Graph control or corresponding to the Report
on which the Sub-Report is based, specified in the Data Source
property for the Sub-Report control, or corresponding to the Query on
which the Text/Query is based, specified in the Data Source property for the Text/Query control.
Use that button to open the Field link editor
Note for a Graph: The Child Data Link property uses one of the field names that will link the current graph with the Parent Data Link of the Report.
Note for a Sub-Report: The Child Data Link property uses one of the field names that will link the current Sub-Report with the Parent Data Link of the Report.
Note for a Cross Table: The Child Data Link property uses one of the field names that will link the current Cross Table with the Parent Data Link of the Report.
Note for a Text/Query: The Child Data Link property uses one of the field names that will link the current Text/Query object with the Parent Data Link of the Report.
Note for Cubes: The Child Fields property uses one of the field names which will link the current cube to the reports Parent field.
See Graph example