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Why does PowerDesigner have a two-level design?

April 26, 2017design powerdesigner two-level

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Why does PowerDesigner have a two-level design?

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A. PowerDesigner is based on the Information Engineering Methodology by James Martin. This methodology is based on a two-level design consisting of a Conceptual Data Model (CDM) and a Physical Data Model (PDM). The aim in separating the database design into a two-step procedure is to greatly simplify the design process that would otherwise be more complicated. The CDM allows the designer to concentrate solely on defining the objects in the information system and the relationships between them, without having to consider the numerous parameters associated with the physical implementation such as data integrity constraints, data access speed and data storage efficiency. The CDM thus provides a clear and succinct picture of the information system, which is independent of the targeted DBMS. A single CDM may therefore be associated with a number of PDMs targeting different DBMS. Q.