Dan Shirah wrote:
Hi gang:
A related question to my last "Clarity needed" post.
I have a tutor table (showing all the tutors), a course table (showing all
the courses), and a course-to-tutor table (showing all the instances of what
tutor teaches what course).
Okay, everything works. Whenever I want to find out what courses a specific
tutor teaches OR what tutors teach a specific course, I simply search the
course-to-tutor table and bingo out pops the answer.
Now, how do you handle the situation when a tutor quits or when a course is
no longer offered?
If I search the course-to-tutor table for all the tutors who teach a course
and find a tutor who is no longer there OR search the course-to-tutor table
for all the courses a tutor teaches and find a course that is no longer
offered, how do you handle the record?
I realize that if either search turns up nothing, I can check for that
situation and then handle it accordingly. But my question is more
specifically, in the event of a tutor quilting OR removing a course from the
curriculum, what do you do about the course-to-tutor orphaned record?
As I see it, my choices are to a) ignore the orphaned record or b) delete
the orphaned record. If I ignore the record, then the database grows with
orphaned records and searches are slowed. If I delete the orphaned record,
then the problem is solved, right?
I just want to get a consensus of how you people normally handle it. Do any
of you see in danger in deleting an orphaned record?
Cheers,
tedd
I guess that all depends.
If you want some kind of historical log of what tutor taught which course
and which courses have previously been offered then I wouldn't delete the
records. Instead I would and something like a "Active" column and use
simple "Y" and "N" vaules to mark each tutor or course as active and then
just re-write your query to only pull tutor's/courses with the "Y" flag.
That would give you a current listing of active courses and who teaches
them, and also retain the historical data if it need to be referenced later.
IMHO forget the active flag, replace it with a field "deleted" which is
a timestamp, then you've got an audit trail of when the it was removed :)
infact often seen three fields on every table, "inserted, updated and
deleted" all timestamps and self explanatory.
regards!
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