2.5-2.5.4 - The first generation of data models was...

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1 The first generation of data models was developed for file system. It was used at the beginning of computers. Next we will learn about two new models that tried to cope with the problems of the file system models: the hierarchical model and the network model. A revolution in the database design was created by the apparition of the relational data model. It allowed the use of tables to store the data and is still the current use model. To simplify the representation to be more similar with how the objects look in reality, the object oriented model appeared, similar with object oriented programming languages (like Java). An adaptation between the relational model and OO models is the extended relational model. The next generation of the models will be semantic oriented, allowing both format and informal representation to be mixed. Such a model is offered by XML. We will briefly discuss about each of these models.
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The first model developed was the hierarchical model. It was organizing the data in a tree like structure, on levels. The levels are named SEGMENTS. The top level segment, containing the root of the tree is named the root segment. Very useful to represent large amounts of data for manufacturing projects, that will keep the parts of different components. While offered significant advantages over the file system, the hierarchical model still was complex to implement and difficult to manage. Also it
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This note was uploaded on 01/22/2011 for the course IT 214 taught by Professor Staff during the Spring '08 term at George Mason.

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2.5-2.5.4 - The first generation of data models was...

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