Foreign Key Constraints

[<kyuubi]

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.





---- Msg sent via Spymac Mail - http://www.spymac.com