Efficient evaluation of XML middle-ware queries

Abstract

We address the problem of efficiently constructing materialized XML views of relational databases. In our setting, the XML view is specified by a query in the declarative query language of a middle-ware system, called SilkRoute. The middle-ware system evaluates a query by sending one or more SQL queries to the target relational database, integrating the resulting tuple streams, and adding the XML tags. We focus on how to best choose the SQL queries, without having control over the target RDBMS.

The Michigan benchmark: towards XML query performance diagnostics

“…While this has been shown to be true for some XML queries in the past [33,37], we show that this is also true for simple indirect containment queries, and queries that search for irregular structures. We also demonstrate that one can use recursive SQL statements to evaluate any structural query in the benchmark; however, using recursive SQL statements in the ORDBMS is much more expensive than using efficient XML structural join algorithms implemented in Timber.…”

“…To generate good SQL queries, we adopted the algorithm presented in [33]. The queries in the benchmark were converted into SQL queries (sanitized to remove any system-specific keywords in the query language) which can be found in the Michigan benchmark's web site [34].…”

Interoperability mapping from XML schemas to ER diagrams

“…The paper describes a language for defining XML views on relational data and gives an algorithm that composes mapping definitions with XQuery statements to obtain new mappings. Moreover, in [35] the authors describe an efficient translation of such mappings to a set of SQL queries to be applied on the original relational data.…”

Efficient schema-based XML-to-Relational data mapping

“…While existing work has focused on the problems of schema mapping [1][2][3][4][5][6][7]9] and query mapping [8,[11][12][13][14][15][16][17][18][19], there is no published linear schema-based data mapping algorithm for mapping ordered XML documents to relational data. Firstly, the schemaoblivious storage schemes [1][2][3]16] use a simple, fixed database schema for XML storage, and the data mapping problem in this context has been addressed by Grust et al in [20].…”

“…Although it presents a brief discussion of schema-based order-preserving schema mapping, no algorithmic details are given for the schemabased data mapping. Thirdly, existing works on query mapping [8,[11][12][13][14][15][17][18][19] assume that the database has already been populated with XML documents, and no algorithms have been published for shredding XML documents into relational data in the context where the database schema is generated from an XML schema. The data translation algorithm presented in [21] does not support recursive XML schemas and does not consider the ordered nature of XML documents.…”