Why OGSA-DAI?
There are a number of reasons why OGSA-DAI is an effective solution to a specific data management problem. OGSA-DAI workflows can represent complex data management scenarios, which involve data access, transformation, filtering, and updating of numerous distributed, heterogeneous databases.
OGSA-DAI is much more than another database connection layer between clients and data. OGSA-DAI is a server-side data workflow engine designed for data integration, federation and distributed query support across multiple types of database and file system.
As well as offering these capabilites, a server that executes workflows has a number of other advantages:
- Thinner clients with less memory and CPU requirements.
- Minimised client-server communication overheads.
- Activities process data on the server, which minimises data movement, as opposed to BPEL or Taverna or web service-based workflow engines which pass data to and fro via web services.
- Data streaming allows activities work on different parts of the data stream in parallel which reduces the memory footprint on the server and can reduce execution times.
A workflow is a simple way, yet very expressive, way of representing a complex set of related, ordered actions.
By providing an intermedate layer, OGSA-DAI also:
- Allows data providers to retain control of their data.
- Provides a layer in which to hide database heterogeneities which can yield thinner clients.
- Provides a place to enforce additional security, for example to hide the actual location of the data, or filter the data according to the rights of clients, and manage access to federations, databases, tables, documents, files, rows, or lines of data.
- Provides a place to define views on read-only databases.
OGSA-DAI is also highly extensible and supports the use of application-specific data resources, activities, security, and presentation layers. It can be viewed as an enabling framework to save development time and allow users to focus on application-specific features, while getting standard functionalities out-of-the-box (e.g. queries, updates, transformations, deliveries).
OGSA-DAI is 100% Java and runs under Windows, UNIX, Linux. It also uses web services and so clients can be written in any language and on any platform that supports web services.
These examples provide a more in-depth view of OGSA-DAI and data workflows.