Hierarchical Data Model
IMS data model
The hierarchical data model is based on a view of the application domain (i.e., the world) as a hierarchical arrangement of concepts where some concepts exist on their own while the others depend on the former. According to this conceptual model, data are organized into records that are recursively composed of other records. Though this paradigm is fairly common in data structures, the term hierarchical model most generally refers to the IMS model, a proprietary DBMS developed by IBM from the 1960s that is still widely used.
The IMS model organizes data in tree structures of records augmented with additional links that compensate for the weaknesses of this base model. Data processing itself is hierarchical, starting from the root of a record tree then parsing the dependent records in depth-first, left-to-right, traversal order.
In 1966, IBM started the development of ICS (Information Control System), a data management software...
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