Image: Hierarchical Model

Description: Hierarchical Model. A data model that do not link records together like a family tree, but each record type has only one owner (e.g., a purchase order is owned by only one customer). Hierarchical data structures were widely used in the first mainframe database management systems. However, due to their restrictions, they often cannot be used to relate structures that exist in the real world.
Title: Hierarchical Model
Credit: http://knowledge.fhwa.dot.gov/tam/aashto.nsf/All+Documents/4825476B2B5C687285256B1F00544258/$FILE/DIGloss.pdf, page 10.
Author: U.S. Department of Transportation vectorization: Own work
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