Segment type and occurrence

The terms segment type and segment occurrence distinguish between a type of segment in the database and a specific segment instance.

This is in contrast to the terms root, dependent, parent, and child, which describe the relationship between segments.

The database shown in How data is stored in a database is actually the design of the database. It shows the segment types for the database. Relationship between segments shows the actual database record with the segment occurrences.

A segment occurrence is a single specific segment. Math is a single occurrence of the COURSE segment type. Baker and Coe are multiple occurrences of the STUDENT segment type.