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  1. #1
    Join Date
    Mar 2012
    Posts
    1

    When to use RENAME Operator

    Hi there...

    I am new to DATABASE course and studying Relational Algebra. I am stuck at a point. The point is, when do we need to Rename the Attributes with the help of rename operator.???


    An early reply would be appreciated.

    Thanks

  2. #2
    Join Date
    Feb 2012
    Posts
    76
    Let's say you have two relations: Employee (Id --> Name, Department) and Department (Id --> Name). You're asked to join them by equating Employee Department with Department Id, and not conflate the different Name attributes.

    In SQL, we can specify the fields we want to join on, but in relational algebra, the join operators are defined based on equally named fields. Parameterizing join operators would make the algebra unnecessarily complex. It's much simpler to define a rename operator.

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