Distributed Database Systems, 1st Edition by Chhanda Ray

Distributed Database Security and Catalog Management

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V1

Name Designation Deptno

J. Lee Manager 10

D. Davis Manager 30

A. Sasmal Manager 20

Fig. 12.1 Result of Query Involving View V1

Select Name, Designation, dname from V1, Department where Designation = “Manager”

and V1.Deptno ⴝ Department.deptno

Assume that a view V2 is created based on the above SQL query. Now any request against the

view V2 will be converted into a data request against the base relations upon which the view V2

is created. Thus, the above query will be modifi ed as listed below, and it will produce the output

shown in fi gure 12.2.

V2

Name Designation Dname

J. Lee Manager Development ...