Suppose we have three tables t (A, B), t2(B, C), and t3(B, D), with all attributes...

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Suppose we have three tables t₁ (A, B), t2(B, C), and t3(B, D), with all attributes de- clared as not null. Consider the expressions (1) t₁ natural left outer join (t2 natural left outer join t3) and (2) (t₁ natural left outer join t2) natural left outer join t3 Give an instance of t1, t2 and t3 such that in the result of the second expression, attribute C has a null value but attribute D has a non-null value. In the above question, is C null and D not null possible in the result of the first expres- sion? Explain why or why not. Suppose we have three tables t₁ (A, B), t2(B, C), and t3(B, D), with all attributes de- clared as not null. Consider the expressions (1) t₁ natural left outer join (t2 natural left outer join t3) and (2) (t₁ natural left outer join t2) natural left outer join t3 Give an instance of t1, t2 and t3 such that in the result of the second expression, attribute C has a null value but attribute D has a non-null value. In the above question, is C null and D not null possible in the result of the first expres- sion? Explain why or why not.

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Certainly Ill provide an example that demonstrates the scenario where in the result of the second ex... View the full answer