Database Reference
In-Depth Information
Data Sharing This benefit of database systems follows from data integration. The
various departments in any enterprise need to share the company's data for proper
functioning. The sales department needs to share the data generated by the account-
ing department through the billing application. Consider the customer service
department. It needs to share the data generated by several applications. The cus-
tomer service application needs information about customers, their orders, billings,
payments, and credit ratings. With data integration in a database, the application
can get data from distinct and consolidated data structures relating to customer,
orders, invoices, payments, and credit status.
Data sharing is a major benefit of database systems. Each department shares the
data in the database that are most pertinent to it. Departments may be interested
in data structures as follows:
Sales department— Customer/Order
Accounting department— Customer/Order/Invoice/Payment
Order processing department— Customer/Product/Order
Inventory control department— Product/Order/Stock Quantity/Back Order
Quantity
Database technology lets each application use the portion of the database that
is needed for that application. User views of the database are defined and con-
trolled. We will have more to say about user views in later chapters.
Uniform Standards We have seen that, because of the spread of duplicate data
across applications in file-oriented data systems, standards cannot be enforced easily
and completely. Database systems remove this difficulty. As data duplication is con-
trolled in database systems and as data is consolidated and integrated, standards
can be implemented more easily. Restrictions and business rules for a single data
element need to be applied in only one place. In database systems, it is possible to
eliminate problems from homonyms and synonyms.
Security Controls Information is a corporate asset and, therefore, must be pro-
tected through proper security controls. In file-oriented systems, security controls
cannot be established easily. Imagine the data administrator wanting to restrict and
control the use of data relating to employees. In file-oriented systems, control has
to be exercised in all applications having separate employee files. However, in a
database system, all data about employees are consolidated, integrated, and kept in
one place. Security controls on employee data need to be applied in only one place
in the database. Database systems make centralized security controls possible. It is
also easy to apply data access authorizations at various levels of data.
Data Independence Remember the lack of data independence in file-oriented
systems where computer programs have data structure definitions embedded within
the programs themselves. In database systems, file or data definitions are separated
out of the programs and kept within the database itself. Program logic and data
structure definitions are not intricately bound together. In a client/server environ-
ment, data and descriptions of data structures reside on the database server, whereas
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