Techniques for adding multiple security policies to a database system

Techniques for managing access to data in a database allow several policies to be applied simultaneously to the same row in a database table, and provide a pluggable module in the form of the database package that allows one or more access control security policies to be added to a common database server without taking the database server off line. Techniques include registering one or more packages of routines with a database management system. An access mediation routine in a first package is invoked for determining whether to allow operation on data in a first table associated with a first policy. Other techniques include, for each operation in an operation set, determining whether to perform the operation on a row of the table based on a set of labels associated with the row. The set of labels correspond to a policy set associated with the table.