exclusive m:m relationship
Date: 2000/01/25
Message-ID: <86kdll$5q3$1_at_gxsn.com>#1/1
Can someone give some advise?
I am trying to implement the following.
A project is done by a number of workers, doing a particular job, which
could be either employed of contracted.
Contractors and employees are stored in different tables. Jobs in projects
could also be done by more than one worker.
I have come up with these two options:
1.
SCHEDULE((Job#(PK,FK),job_type(FK), emp#(PK,FK),contr#(PK,FK))
Each record refers to either employee or contractor exclusively.
2.
SCHEDULE(Job#(PK,FK), job_type(FK), staff#(PK,FK))
Where staff number is either an employee number or contractor number.
The two could be distinguished by starting with a different letter.
I am not quit sure which option is the best way of implementing this and why.
Thanks in advance for any suggestions.
Markus Received on Tue Jan 25 2000 - 00:00:00 CET