By Mark Levene
This monograph describes a style of knowledge modelling whose uncomplicated objective is to make databases more straightforward to exploit through supplying them with logical facts independence. to accomplish this, the nested UR (universal relation) version is outlined by means of extending the classical UR version to nested relatives. Nested kinfolk generalize flat relatives and make allowance hierarchically based items to be modelled at once, while the classical UR version permits the person to view the database as though it have been composed of a unmarried flat relation. the writer offers a entire formalisation of the nested relational version, which integrated null values into the version. sensible facts dependencies and the classical suggestion of lossless decomposition are prolonged to nested kin and a longer chase process is outlined to check the pride of the information dependencies. The nested UR version is outlined, and the classical UR version is proven to be a distinct case of the nested model.This signifies that an UR interface canbe applied through the use of the nested UR version, hence gaining the complete benefits of nested kin over flat relations.
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The Nested Universal Relation Database Model by Mark Levene