I have not looked at the database but it sounds like Status is a derived value and should not be stored.
Presumably you have records for loan transactions. A book that has been loaned and not returned obviously has a status of ON LOAN. Status should be calculated in the recordsource query of the form or report used to display this information.
Storing derived information not only increases the size of the database unnecessarily it allows the potential for conflicing information to be held and is hence a breach of normalization.