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  1. #1
    Join Date
    Jan 2005
    Posts
    3

    Exclamation relation cardinality/selectivity (was "A difficult question, need help")

    Given is a relation R (A1,A2, A3) with three attributes!
    c (A2) = 2 c: cardinality
    s (A2) = 64 s: selectivity
    An index (binary tree) is created for A2!
    What is the depth of a binary tree T(A2) in best case?
    What is the depth of a binary tree T(A2) in worst case?

  2. #2
    Join Date
    Feb 2004
    Location
    In front of the computer
    Posts
    15,579
    Assuming you are using the standard definitions for cardinality and selectivity or a relation, the specified relation can't exist, so both answers are NULL.

    -PatP

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