Thanks to Tim Fee.
This program displays data from three tables with a hierarchical relationship. Records in table 1 are related to any number of records in table 2. Records in table 2 are related to any number of records in table 3.
When you select a record from table 1, the program lists the corredponding records in table 2. When you select a record in table 2, the program displays the corresponding records in table 3.
A TreeView displays the whole hierarchy for the table 1 record you selected.
See the code for details.