An efficiently updatable index scheme for structured documents

We propose an efficiently updatable index scheme for XML documents. This index scheme consists of four types of indices. Content index manages occurrence positions of words, element names, attribute names and attribute values. Local structure index manages logical structure of each document. Global structure index summarizes logical structure of document instances for a DTD. The last one is called structure meta index, and keeps, for each element, the number of local structure indices and global structure indices which include the element. Using our four types of indices, therefore, a wide range of queries over structured documents can be processed efficiently. We compare our indices with existing indices in terms of index size, update cost and retrieval cost