Question

can you answer part e of the question

Q.31 Answer the following questions (a) Explain difference between lossy decomposition and lossless decomposition (b) If you write a SQL statement to inner join the following two tables based on Plocation value as inner join condition, is the result table lossy or lossless? (Explain why?) EMP LOCS P.K EMP PROJ1 Hours Pname Plocation Р.К. (c) Given a relation schema R ={SSN, Ename, Pnumber, Pname, Plocation, Hours) R is decomposed to R1, R2, R3 as shown below. R, = EMP = { SSN. Ename)、R: = PROJ-| Pnumber, Prame, Plocation) R WORKS ON-SSN, Pnumber, Hours) Set of functional dependencies F is given as follows: F-SSNEname; Pnumber>Pname, Plocation; SSN, PnumberHours (d) Explain the difference between 3NF and BCNF (e Explain whether the following EMP relation of the company database is in 4NF. Note: 4NF does not allow more than one multivalued dependencies in a relation (table). If the EMP relation is not in 4NF, decompose the EMP relation into 4NF relations (tables). EMP Smith Smith Smith Smith John Anna Anna John Ename: Employee Name Pname: Project Name Dname: Dependent Name

Answer 1

a) The information will not lose from the relation when decomposed. The join would result in the same original relation Butt. When a relation is decomposed into two or more relational schemas, the loss of information is unavoidable when the original relation is retrieved b) Emp_locs(ename,plocation) Emp_proj1(ssn.pnumber,hours,pname,plocation) Here we can see that ename is not present in Emp_proj1 so it is called Loss of information and it is lossy decomposition.

c) Here we can see that information we can see that we can find out all the field are present in three Relations like R1,R2,R3 so it is here Loose less decomposition. d) Be in BCNF: In 3 Normal Form&Any dependencies A>B Here A should be Super Key But Be in 4th Normal for they are 3rd Normal as well as BCNF form multi- valued dependency In 4th form, there are no multi-valued dependencies of the tables, but in BCNF, there can be multi-valued dependency data in the tables

e) As we can ename smith has a project x,y and department John,anna as well here no duplicate tuple we can find out it already in 4th Nor valued dependency

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