What is theta join explain, Database Management System

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What is theta join explain?

Theta  Join  - The  theta  join  operation  is  an  extension  to  the  natural-join operation which permits us to merge selection and a Cartesian product within a single operation. Consider relations r(R) and s(S), and let θ be a predicate on attributes in the schema R ∪ S. The theta join operation r θ s is described as follows:

r θ s = σθ (r x s)

 


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