The XML Indexing and Storage System (XISS)
is a database research project in the
Computer Science Department
at the University of Arizona.
It provides a series of techniques to store, index and query XML data.
XISS utilizes the extended
preorder numbering scheme for
XML documents. The extended preorder numbering scheme
provides a way to encode the elements and
attributes in an XML document, such that the
ancestor-descendant relationship can be determined quickly and future
insertions can be accommodated gracefully. This
numbering scheme also provides opportunities for storing XML data
using relational databases, which is demonstrated in
the XML Indexing and Storage System using RDBMS (XISS/R).
XISS provides a framework to
utilize the extended preorder numbering scheme. Within the framework, it
implements several XML path expression query processing algorithms including
EE-join, EA-join and KC-join. This project is further extended by including
partition-based algorithms within the framework.
XISS/R implements the XML
indexing and storage system on top of a relational database system. Since
there are several choices on how to store the XML data using the extended
preorder numbering scheme, we implemented several relational schemas and
compared their performances.