Suppose that R =(R, F) is a relation schema and R 1 =(R 1 ; F 1 ), ..., Rn; Fn) is its decomposition. Let r be a valid relation instance over R and ri = ?(r). Show that ri satis?es the set of FDs F i and is therefore a valid relation instance over the schema R i.
What will be an ideal response?
Since Fi is entailed by F and all of the attributes mentioned in Fi are contained within Ri, it follows that the projection of r on Ri satis?es every FD in Fi.
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