Data Exchanges, XML, and Why the Exchange Problem Is Still Unsolved

To understand the exchange of data between systems, we may first consider conceptual models for the exchange of data. The first model relies on a central data structure for passing data among nodes. This is the model commonly used in meteorology and oceanography communities. A second model is more formal, and relies on instances of a common data model. Nodes exchange data with an instance of a common database, with data replicated between the common instance databases. The third conceptual model deals with wrapper software that encapsulates the data asset. Applications query the data asset using an intermediate layer, sometimes called an integrator or mediator, to identify the required data asset. The mediator then deals with the critical data issues like consolidation of parameter codes, units, replicate data, metadata content and multiple structures. The resulting data is provided to the user as a coherent and internally consistent data set.