20th International Conference on Data Engineering (ICDE'04)
Recursive XML Schemas, Recursive XML Queries, and Relational Storage: XML-to-SQL Query Translation
Boston, Massachusetts
March 30-April 02
ISBN: 0-7695-2065-0
We consider the problem of translating XML queries into SQL when XML documents have been stored in an RDBMS using a schema-based relational decomposition. Surprisingly, there is no published XML-to-SQL query translation algorithm for this scenario that handles recursive XML schemas. We present a generic algorithm to translate path expression queries into SQL in the presence of recursion in the schema and queries. This algorithm handles a general class of XML-to-Relational mappings, which includes all techniques proposed in literature. Some of the salient features of this algorithm are: (i) It translates a path expression query into a single SQL query, irrespective of how complex the XML schema is, (ii) It uses the "with" clause in SQL99 to handle recursive queries even over non-recursive schemas, (iii) It reconstructs recursive XML subtrees with a single SQL query and (iv) It shows that the support for linear recursion in SQL99 is sufficient for handling path expression queries over arbitrarily complex recursive XML schema.
Citation:
Rajasekar Krishnamurthy, Venkatesan T. Chakaravarthy, Raghav Kaushik, Jeffrey F. Naughton, "Recursive XML Schemas, Recursive XML Queries, and Relational Storage: XML-to-SQL Query Translation," icde, pp.42, 20th International Conference on Data Engineering (ICDE'04), 2004