Signature file generation techniques for query processing in object-oriented databases

A signature file access method is proposed for efficient evaluation of queries having conditions of nested attributes in the class-attribute hierarchy. The method requires the path of object identifiers in the index for the processing of multi-key queries. Previous signature file generation techniques have some problems such as false attribute match and poor retrieval performance. In order to solve these problems, the proposed signature file generation technique requires to maintain a separate signature file for each class with path of object identifiers. By partitioning large signature file into small sized ones for each class, inter-class attributed identification problems do not occur. Also retrieval performance can be improved by selectively reading signature files of classes used in the query. Signature formation technique is also proposed for the attribute of list data type.