Friend Function Orientation in Database Management System

Discuss that designing the database management,how to realize authorization management by friend class programming in database security management.Utilizing friend function method in C++,that is,friend function basic idea and design method and friend class use rule,profit authorization management.Dependent on appropriate program analysis,gives right friend function design method and basic rule.Using the friend function design,completely achieve database management,but must give up encapsulation character of class.