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What is OGSA-DAI?

OGSA-DAI is a middleware product that allows data resources, such as relational or XML databases, to be accessed via web services. An OGSA-DAI web service allows data to be queried, updated, transformed and delivered. OGSA-DAI web services can be used to provide web services that offer data integration services to clients.

OGSA-DAI web services can be deployed within a Grid environment. OGSA-DAI thereby provides a means for users to Grid-enable their data resources.

Motivation

OGSA-DAI is motivated by the need to:

  • Allow different types of data resources - including relational, XML and files - to be exposed onto Grids.
  • Provide a way of querying, updating, transforming and delivering data via web services.
  • Provide access to data in a consistent, data resource-independent way.
  • Allow metadata about data, and the data resources in which this data is stored, to be accessed.
  • Support the integration of data from various data resources.
  • Provide web services that can be combined to provide higher-level web services that support data federation and distributed query processing.
  • To contribute to a future in which scientists move away from technical issues such as handling data location, data structure, data transfer and integration and instead focus on application-specific data analysis and processing.

What Does OGSA-DAI Do?

OGSA-DAI can support the following:

  • Different types of data resources - including relational, XML and files - can be exposed via web services. A number of popular data resource products are supported.
  • Data within each of these types of resource can be queried and updated.
  • Data can be transformed (using XSLT).
  • Data can be delivered to clients, other OGSA-DAI web services, URLs, FTP servers, GridFTP servers, or files.
  • Requests to OGSA-DAI web services have a uniform format irrespective of the data resource exposed by the service. (though the actions specified within each request may be data resource-specific).
  • Information on the data resources exposed by an OGSA-DAI web service and the functionality supported by the service can be accessed by clients.
  • OGSA-DAI users can extend OGSA-DAI web services to expose their own data resources and to support application-specific functionality, in addition to that provided by OGSA-DAI.

OGSA-DAI provides web services compliant with the Web Services Resource Framework (WSRF) http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=wsrf.

OGSA-DAI and DAIS

The DAIS - Database Access and Integration Services - Working Group of the Open Grid Forum (OGF) is formulating standards for database access and integration services.

The development of OGSA-DAI has been occurring in parallel to the development of these specifications. OGSA-DAI influences, and is influenced by, this work. OGSA-DAI is currently based upon the DAIS specifications of March 2003. It is intended that OGSA-DAI will eventually provide a reference implementation of the final version of these standards.

Further information on the OGF and DAIS are available from: