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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 the General Transformation Rules for Relational operations? Ans: The transformation rules transform one relational algebra expression to AN EQUIVALENT ONE 1. E
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An ideal data dictionary should have everything a DBA wants to know about the database. 1 Conceptual, External, and internal database descriptions. 2. Descriptions of attr
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When is a transaction rolled back? Any changes that the aborted transaction made to the database must be uncompleted. While the changes caused by an aborted transaction have be
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