> On Wednesday 26 May 2004 11:22 pm, kyuubi@stripped wrote:
> > Hi, I am trying to use the foreign key constraints from InnoDB
> > and creating indexes is a requirement for foreign key.
> > The problem is that by creating index for my foreign key,
> > it does not allow my foreign key to have null or blank values which my
> > records will have. For eg. a BorrowerID is a foreign key on a Book
> > but when the book is not borrowed, the BorrowerID will be null and I
> > seem to import the data containing null values for the foreign key. Is
> > there a way to solve this?
> > Thanks.
> I am not to sure how its possible to fix it.. Thinking about this.. I
> have a bookid which is never null. Considering no matter if the book is
> or not, you have that book. I then would have a borrow table, lets say, as
> the foreign key would be bookid.. I date borrowed, and date returned would
> how I would know if its out or not..
> Just thinking off the top of my head as there probably is a better way to
> I am sure there are other ways to do this.. Foreign keys can't be null.
Why not? What's wrong with this:
FK from Books.BorrowerID to Borrower.BorrowerID
I haven't checked, but this _should_ be possible.
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