Relational Operator - Rename

Relational Algebra Between Sql And Query Plan

About

Rename or (renaming) is a relational operator that rename:

  • a relation
  • or an attribute of the relation

Syntax

<MATH> \LARGE \rho_{a/b} R </MATH> rename the attribute a from R to b

in SQL, the rename operator is called as

select a as b from R

Example

Rename the 4 attributes {A, B, A, C} resulting from the cross product between R1 and R2 to {A_1, B, A_2, C} <MATH> \LARGE \rho_{A_1,B,A_2,C} \left( \pi_{A,B}R_1 \times \pi_{A,C}R_2 \right) </MATH> where:





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