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It defines that the tuple in one relation that refers to another relation must refer to an existing tuple in that relation. This constraint is states on two relations (not essentially distinct). It uses a concept of foreign key and has been dealt with in more factors in the next unit.
Example
In the example given above, the value of C^ in every R tuple is matching with the value of C# in some S tuple. If a tuple has values (A6, B2, and C4) is added then it is invalid as referenced relation S doesn't contain C4. Therefore, it will be a violation of referential integrity constraint.
Identify the need and use of data control through problem solving, illustration
All edges of a cube are expanding at a rate of 6 centimeters per second. How fast is the surface area changing when each edge is (a) 2 centimeters and (b) 10 centimeters?
Creating views with check option : This option limits those updates of data values that cause records to go off the view. The following instance tells this in more detail: Examp
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1. Will you advise that your organization uses open source software and why? 2. Why is it important for business managers to have a basic understanding of the software development
statical data
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