Hi, > On Wednesday 26 May 2004 11:22 pm, [EMAIL PROTECTED] 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 table, > > but when the book is not borrowed, the BorrowerID will be null and I can't > > 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 would > have a bookid which is never null. Considering no matter if the book is out > 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 be > 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 do > it. > > I am sure there are other ways to do this.. Foreign keys can't be null.
Why not? What's wrong with this: BORROWER BorrowerID BOOKS BookID BorrowerID (nullable) FK from Books.BorrowerID to Borrower.BorrowerID I haven't checked, but this _should_ be possible. With regards, Martijn Tonies Database Workbench - developer tool for InterBase, Firebird, MySQL & MS SQL Server. Upscene Productions http://www.upscene.com -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
