Database Reference
In-Depth Information
ON (PARENT.INSTRUMENT_ID = CHILD.SECTION_ID)
ORDER BY PARENT.NAME, CHILD.NAME;
Figure 10.24 contains the result of the query. Notice how the Alto
Horn, Baritone Horn, and Clarinet are part of Woodwind instruments.
Additionally, Woodwind instruments are part of Wind instruments. That is
a three-layer hierarchical representation.
Note:
See Chapter 13 for details on hierarchical queries.
Figure 10.24
A Hierarchical
Data Fishhook
Self-Join.
