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Under what condition does the selection operation distribute over theta join operation ?


Let R and S are two relations then which one of the following statements about the above condition is TRUE ?


i)  σC (R ⋈ S) ≡  (σC1 (R)) ⋈ (σC2 (S)) 


ii)  σC (R ⋈ S) ≡ (σC (R)) ⋈ R


iii)  σC (R ⋈ S ) ≡ σC2 ( (σC1 (R)) ⋈ S)


iv)  σC (R ⋈ S ) ≡  σC1 (  R ⋈ (σC2  (S)))

  A      i, iii      

  B      i , ii, iii, iv

  C      ii , iii  

  D      i, ii 

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