Practically all analytical processes are driven by database queries. A database query is a machine readable question presented to a database in a predefined language.
Unlike other code systems, which either have no hierarchy or a hierarchy that is fully represented within the code (e.g. H65.9), just retrieving the SNOMED CT codes recorded in a patient record does not fully utilize the analytics capabilities of SNOMED CT. To get the most benefit from using SNOMED CT in patient records, one must be able to not only query the records themselves, but also query SNOMED CT.
In this section, we describe how record and terminology queries can work together to perform powerful queries over SNOMED CT enabled data. In section 10 User Interface Design, we will then consider how user interfaces can be designed to make these queries more accessible to non-technical users.