Access control for deductive databases by logic programming

We show how logic programs may be used to protect deductive databases from the unauthorized retrieval of positive and negative information, and from unauthorized insert and delete requests. To achieve this protection, a deductive database is expressed in a form that is guaranteed to permit only authorized access requests to be performed. The protection of the positive information that may be retrieved from a database and the information that may be inserted are treated in a uniform way as is the protection of the negative information in the database, and the information that may be deleted.