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