Database Reference
In-Depth Information
general terms, relational database systems have the following characteristics:
 All data is conceptually represented as an orderly arrangement of data into rows and
columns, called a relation.
All values are scalar. That is, at any given row/column position in the relation there is one
and only one value.
 All operations are performed on an entire relation and result in an entire relation, a
concept known as closure.
Advantages of a Relational Database
The relational database model provides a number of advantages over network
and hierarchical models, such as the following:
 It ensures the accuracy of the data due to data integrity that is built into the model at the
field level. It avoids duplication of records and to detect missing primary key values. At the
relationship, it ensures that the relationship between a pair of tables is valid. At the busi-
ness level it ensures that the data is accurate in terms of the business itself.
 Any change in logical design or physical implementation of database will affect the ap-
plications developed upon it.
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