Paul McNett wrote: > Uwe Grauer wrote: >> What is a table without a primary key good for? >> Can you come up with a practical use for this? > > An intermediary table for getting M:M joins that doesn't have any other > meaningful information other than the two foreign keys really doesn't > require a primary key. IOW: > > > customers > --------- > pk > name > ... > > > categories > ---------- > pk > name > ... > > > cust_cat > -------- > cust_fk > cat_fk > > > I've gotten in the habit of making a cust_cat.pk anyway, even though it > isn't ever used anywhere. I could also do (cust_fk, cat_fk) as the PK > but I've just never taken to that approach. > >
In some big projects i have learned to always use a technical primary key. That's the only way to be able to change your design if necessary in all circumstances. It isn't worth the effort to reduce the size of your record, instead you have to be able to represent your data structures in a normalized way. So i always use a singe primary key field which never has to be changed during the lifetime of the data. Uwe _______________________________________________ Post Messages to: [email protected] Subscription Maintenance: http://leafe.com/mailman/listinfo/dabo-dev Searchable Archives: http://leafe.com/archives/search/dabo-dev This message: http://leafe.com/archives/byMID/dabo-dev/[EMAIL PROTECTED]
