GMD-IPSI XQL Engine

The GMD-IPSI XQL engine is a Java based storage and query application for large XML documents. It is founded on two major technologies,

1. a persistent implementation of W3C-DOM Document objects,
2. a full implementation of the XQL language.

From the XQL FAQ:

XQL is a query language that uses XML as a data model, and it is very similar to XSL Patterns. XQL expressions are easily parsed, easy to type, and can be used in a variety of software environments - as part of a URL, in XML or HTML attributes, in programming language strings, etc.

The XQL engine implements the XQL W3C-QL '98 workshop paper syntax version of XQL. Indexing and query optimization techniques are implemented in the engine, especially multiple queries on a single document are accelerated.

The persistent DOM (PDOM) implements the full W3C-DOM API on indexed, binary XML files. Documents are parsed once and stored in binary form, accessible to DOM operations without the overhead of parsing them first. A cache architecture additionally increases performance. The XQL processor can be used to query PDOM files.

The GMD-IPSI XQL engine was developed as a research project in GMD's XML competence center by Gerald Huck, with contributions by Ingo Macherius. The project homepage is at http://xml.darmstadt.gmd.de/xql/.

This software is free for non-commercial use and evaluation, see the license page for details. Commercial users must license the improved commercial verison if they want to continue to use the software after a 30 days trial period. See http://www.infonyte.com for contact information and product details.