3.1 - In the previous chapter we learned that the...

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In the previous chapter we learned that the relational data model has important characteristics: It is structural independent, which means that a change in a file structure will not affect how data is accessed (for instance when you add a new attribute to an entity). It is data independent, which means that a change in the data storage characteristics will not affect how data is accessed (for instance increasing the size for the data, or changing the format). It is physical independent, which means that the designer can examine the model’s logical structure without considering the physical aspects of data storage and retrieval. It has a medium degree of abstraction, being hardware independent, but being software dependent (different DBMS will implement the model in different ways). It may be considered an internal model of how a DBMS is implementing a database using relational tables.
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You must be careful to not confuse the relational model with the entity relationship model. The entity relationship model is a conceptual model, that uses a graphic paradigm to
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3.1 - In the previous chapter we learned that the...

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