Report on Ordering Key DS CE

In this document, we report the results of our core experiment on the Ordering Key D. The concept of the Ordering Key D has been proposed for the first time in Beijing meeting [m6227] as a part of the generic Weight DS. According to the discussions during that meeting the Weight DS has been specialized in order to obtain exclusively ordering functionalities [w3473]. At the same time the demo showed in Beijing seemed to demonstrate the useful of the ordering beetwen entities of various types. At the following meeting a specialized and improved semantic and syntax have been proposed. In spite of positive results about its utility, as shown in the demo [m6588] and also in the document [m6491], it was not clear the use of XPath syntax as mechanism to obtain reference to entities. At the La Baule meeting the DDL group had not yet decided about the use of XPath as reference datatype. In conclusion the aim of this CE was not to demonstrate the OrderingKey effectiveness but to investigate about its syntax [w3630].