I don\'t even know where to begin on this one, please help!. Here is the problem

Question

I don't even know where to begin on this one, please help!. Here is the problem:

Develop an estimation formula for the size of the result of the JOIN of two relations of cardinalities c1 and c2 respectively, making the assumption that the values of the JOIN attributes are uniformly distributed. Assume that the relations have k1 and k2 distinct values of the JOIN attribute respectively, and that r of these keys are common to both relations. HINT: This question is asking that you create a formula for estimating the RESULT-SET of joining two relations that obey certain constraints on cardinality, values, etc. This question is an important determinant of performance – especially when relation fragments of varying sizes have to be shipped across networks.

Explanation / Answer

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You will get all this here in this book 'Silberchatz DataBase Management Systems'.

You can find it here

http://www.cse.iitb.ac.in/~sudarsha/db-book/slide-dir/

You have to look into the Chapter 14 of this book. It contains all the explanations you need.

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