Concept Hierarchy Queries
The SQL queries in this section require that you extend the Output Database by adding the Snomed relationship definitions table. You can download the SQL file containing these definitions and install them following these instructions.
Concept hierarchies allow you to conveniently find a large set of related terms specifying only a single concept. It is a powerful query pattern, and makes the initial setup well worth the effort. An explanation of the SNOMED ontology, and how it encodes relationships between concepts, is found here.