Normal Forms

The relation Viewing is intended to record information for a house agent about the details of properties on his books and a history of their viewings together with the outcome of a viewing (whether the customer was definitely interested in buying the property, definitely not interested or still thinking about it). The following gives the relational heading: Viewing (PropertyCode, CustomerCode, DateOfViewing, Address, CouncilTaxBand, CouncilTax, CustomerName, CustomerContactNumber, OutcomeOfViewing) The following gives some sample data from the corresponding relational table: The first row in this table gives the information that property P1, 1 Cherry Gardens, Notlaw, ZZ1 3YY, being in council tax band B and so paying £1500 per year, was viewed on 24 December 2012 by customer C1, John Smith, with contact number 0799 9999999, who is not interested in buying it. The following are some of the non-trivial functional dependencies on Viewings  (a) Demonstrate that Viewing is subject to insertion, deletion and amendment anomalies.  (b) From FD1–FD6, derive two moren on-trivial functional dependencies where the determinant is irreducible and part of the primary key. Justify your derivations.  (c) Justify the statement that Viewing is not in second normal form (2NF). Write down the headings of relations in 2NF that will result from a non-lossy decomposition of Viewing. Justify that these relations are in  2NF. (d) Are each of the relations resulting from the decomposition in part (c) in third normal form (3NF)? Justify your answer. For each relation which is not in 3NF, write down the headings of the relations in 3NF which result from a non-lossy decomposition of that relation. Justify your answers.

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