Method for establishing index library, search method and method for updating index library

The invention discloses a method for establishing an index library, a search method and a method for updating an index library. The method for establishing the index library comprises the following step: establishing a permission index field for each resource unit in the index library, wherein one permission index field is composed of multiple pieces of permission information. According to the method, resource unit utilization is classified by the permission index field comprising the multiple pieces of permission information; and when the permission information is changed, only single permission index field is updated so as to achieve the goal of rapid updating, thus, a permission search library can be finished as fast as possible when the data is updated.