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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.
What are composite attributes? Composite attributes can be separated in to sub parts.
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Hierarchical model is also known by? A hierarchical model is also known as a Tree structure.
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Which are the two ways in which entities can participate in a relationship? Total and partial are the two ways in which entities can participate in a relationship
What is a Transaction? A transaction is an event which happens on the database. Generally a transaction reads a value from the database or writes a value to the database. If y
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