I have a small database (16 entities and about a 70 attributes) but I cant work out the most logical primary key for one of the tables.
I have student and next of kin. A student can have one next of kin but a next of kin can be the NOK for many students. I thought that I should use NOKname and NOKrelationship (relationship to student as a composite key however if for example the NOK has two children they may be the NOK for both and be the father of both!
Attributes of NOK:
NName
NAddress
NTelNumber
NRelationship
Attributes of Student:
StudentNumber
PFirstName
PSurName
PAddress
PDOB
DateRegistered
Sex
PTelNumber
MaritalStatus
DateWaitingList
DatePlaced
ExpectedLengthStay
DateLeave
Thank you for any advice that you can offer!
Add an Id to the NOK table and add NOKId to the Student table. This will allow one NOK for each student but the NOK can be for multiple students.