Normal Form
Q21.
Let R (A, B, C, D, E, P, G) be a relational schema in which the following functional dependencies are known to hold: AB \to CD, DE \to P, C \to E, P \to C and B \to G. The relational schema R isQ22.
Consider the following relational schema: Suppliers(sid:integer, sname:string, city:string, street:string) Parts(pid:integer, pname:string, color:string) Catalog(sid:integer, pid:integer, cost:real) Assume that, in the suppliers relation above, each supplier and each street within a city has a unique name, and (sname, city) forms a candidate key. No other functional dependencies are implied other than those implied by primary and candidate keys. Which one of the following is TRUE about the above schema?Q23.
Let R (A, B, C, D) be a relational schema in which the following functional dependencies are known to hold: A \to B, \; B \to C, \; C \to D and D \to B. The decomposition of R into (A,B), (B,C), (B,D)Q24.
Consider the following relational schemes for a library database: Book (Title, Author, Catalog_ no, Publisher, Year, Price) Collection (Title,Author, Catalog_ no) with in the following functional dependencies: I. Title Author \rightarrow Catalog_no II. Catalog_no \rightarrow Title Author Publisher Year III. Publisher Title Year \rightarrow Price Assume {Author, Title} is the key for both schemes. Which of the following statements is true?Q25.
Relation R has eight attributes ABCDEFGH. Fields of R contain only atomic values. F=\{CH\rightarrow G, A\rightarrow BC,B\rightarrow CFH,E\rightarrow A,F\rightarrow EG\} is a set of functional dependencies (FDs) so that F^{+} is exactly the set of FDs that hold for R. The relation R isQ30.
Consider the following implications relating to functional and multivalued dependencies given below, which may or may not be correct. i. if A \rightarrow \rightarrow B and A \rightarrow \rightarrow C then A \rightarrow BC ii. if A \rightarrow B and A \rightarrow C then A \rightarrow \rightarrow BC iii. if A \rightarrow \rightarrow BC and A \rightarrow B then A \rightarrow C iv. if A \rightarrow BC and A \rightarrow B then A \rightarrow \rightarrow C Exactly how many of the above implications are valid?