ToX Toronto XML Server
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The Toronto XML Server is a repository for XML data and metadata, which supports real and virtual XML documents.
Real documents are stored as files or mapped into relational or object databases, depending on their structuredness; indices are defined according to the storage method used.

Virtual documents can be remote documents, defined as arbitrary WebOQL queries, or views, defined as queries over documents registered in the system.

The system catalog contains metadata for the documents, especially their schemata, used for query processing and optimization. Queries can range over both the catalog and the documents, and multiple query languages are supported.

The project started recently and is under active development.

More details can be found in this paper.


The current version of ToX supports the following features:

- Multiple catalogs:
  • Each catalog contains a set of collections and documents.
  • Documents are unique within the catalog, but can belong to several collections.
- Collection management:
  • Automatic selection of suitable collections to store a document based on type conformance checking between DTDs. Among all the available collections the ones with supertypes DTD are going to be selected.
  • Simple metadata associated to collections.
  • DTDs associated to collections.
  • Enforcement of document conformance to collection's DTD.
  • Type conformance checking between document's and collection's DTD.
- Multiple backends:
  • File system backend. Documents are stored as text files.
  • Relational backend. Documents are mapped to tables in a DB2 database.
  • ToXin backend. Documents are loaded into main memory into a specially designed data structure for fast access.
  • All backends are implemented on top of a common navigational interface.
- XQuery query processor:
  • Implementation of the XQuery Core standard of the W3C.
  • Queries can be range on specific documents or whole collections.
  • Queries can transparently integrate results from different collections and different backends.
- ToXin index:
  • Indexing scheme for XML data that fully exploits the overall path structure of the database in regular path query evaluation.
  • Used for processing documents on the file system backend (version 1.1)
- Text index:
  • Indexing of the data values of XML documents (version 1.1)
  • The XQuery query processor was extended with new build-in functions to exploit the text index.
  • Web Services Interface.
  • Java components.
  • C++ components.
  • JNI technology.
-A demo can be found here. Zipped sample queries can be downloaded from here.


Related Publications:


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