Database Reference
In-Depth Information
its own. In fact, the only information about a view that is stored in the database is its struc-
ture. Many major RDBMS programs support views, but some (such as Microsoft Access)
refertothemas saved queries. YourspecificRDBMSprogramwilldeterminewhetheryou
refer to this object as a query or a view.
Views enable you to see the information in your database from many different aspects,
providing you with a great amount of flexibility when you work with your data. You can
create views in a variety of ways and they are especially useful when you base them on
multiple related tables. In a school scheduling database, for example, you could create a
view that consolidates data from the STUDENTS, CLASSES, and CLASS SCHEDULES
tables.
Figure 3.10 shows a view called INSTRUMENT ASSIGNMENTS that is composed of
fields taken from the STUDENTS, INSTRUMENTS, and STUDENT INSTRUMENTS
tables. The view displays data that it draws from all of these tables simultaneously, based
on matching values between the S TUDENT ID fields in the STUDENTS and STUDENT
INSTRUMENTS tables, and the I NSTRUMENT ID fields in the INSTRUMENTS and
STUDENT INSTRUMENTS tables.
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