0 0 votes Consider an entity employee with attributes (EmpID, Empname, Deptname, Salary, mobno, Project ID, Designation) No two employee with same name and No two employee with same ID. An employee can have more than 1 mobileno and can work on one project only. A relation is designed satisfying the requirement of 2NF. The number of super keys there in the table containing attribute project ID are __________. Databases databases database-normalization + – Çșȇ ʛấẗẻ 1.6k views answer comment Share Follow Print See all 4 Comments 4 4 Comments reply ST commented Jan 4, 2017 reply Follow flag 48 ? 1 1 replyShare Çșȇ ʛấẗẻ commented Jan 4, 2017 reply Follow flag how ?? 0 0 replyShare ST commented Jan 4, 2017 reply Follow flag 2 candidate keys are there. Total 6 attributes in the table. Total superkeys will be : $2^5 + 2^5 - 2^4$ = 48 1 1 replyShare Varun Raj Akula commented Mar 6, 2022 reply Follow flag It is mentioned “An employee can have more than 1 mobileno and can work on one project only. A relation is designed satisfying the requirement of 2NF.”. but we haven’t used anywhere in the solution. Can anyone plz provide the detailed solution. covering all the points mentioned in Question text. 0 0 replyShare Please log in or register to add a comment.
4 4 votes There r total 7 attributes first seperate Project ID now we have 6 attributes now we have 2 candidate keys EmpID, Empname as given in question super keys using EmpID =25=32 super keys using Empname 25=32 repeated superkeys =24 =16 so by using principle of enclusion-exclusion n(EmpID U Empname)=32+32-16=48 now add Project ID to all these 48 ans =48 saurabh rai answered Jan 4, 2017 saurabh rai comment Share Follow See all 3 Comments 3 3 Comments reply Çșȇ ʛấẗẻ commented Jan 4, 2017 reply Follow flag the statement "A relation is designed satisfying the requirement of 2NF. " where it has used as given . 0 0 replyShare saurabh rai commented Jan 4, 2017 reply Follow flag As per given information we have 2 nontrivial dependency one for EmpID nd other for Empname nd both r super key (every cand key is also super key) so it is in bcnf hence it is in 2NF also... 0 0 replyShare Warlock lord commented Apr 25, 2017 reply Follow flag Can you please let me know the source of your understanding? I mean this explanation is great but it didn't occur naturally to me. And also it's mentioned that phone number is multi-valued, shouldn't we do anything about that? 1 1 replyShare Please log in or register to add a comment.
