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What are the General Transformation Rules for Relational operations?
Ans: The transformation rules transform one relational algebra expression to AN
EQUIVALENT ONE
1. Employed by the query optimizer to optimize query tree
2. Any type of rule, if applied, ensures that the resultant tree is equivalent → resulting execution plan is equivalent
General Transformation Rules is as follow:
1. Commutativity of s: The s operation is commutative:
Having Clause with sub queries: First we have to recollect the GROUP BYclause. The following query searches the minimum salary in every department. SELECT DEPTNO, MIN (SAL)
The database depicted in the Visio diagram describes Proceeding , Article , Researcher , article PublishedIn a proceeding, article WrittenBy researchers and proceedings Edi
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Difference between SQL and SQL*Plus SQL SQL*Plus SQL is a language SQL *Plus is an environment It is bas
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What is the use of rename operation? Rename operation is used to rename both relations and an attributes. It uses the as clause, taking the form: Old-name as new-name.
What is a virtual table that draws its data from the result of an SQL SELECT statement? View is a virtual table that draws its data from the result of an SQL SELECT statement.
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