Diploma Thesis, TU-Vienna, 2011

In the .NET environment LINQ (Language Integrated Query) has established as universal component for data inquiry. The creation of the SQL-like query is strictly separated from the execution and interpretation and therefore represents an appropriate foundation for extensions. The "Space-based computing" or "Shared Data Spaces" forms the basis for the XVSM (eXtensible Virtual Shared Memory) middleware solution that consistently uses coordinators to shift query logic from the application code into the abstraction framework. The initial intention of this work was to extend XVSM with LINQ in order to enrich the API with uniform and versatile query capabilities.

 

A portion of this thesis presents a LINQ adapter for XcoSpaces, the .NET reference implementation of XVSM. These module converts LINQ queries, so-called expression trees, to the matching LindaCoordinator inquiry which can be interpreted by XcoSpaces. Because this coordinator is based on template matching, the support of LINQ functionality is mainly restricted to equality comparisons.

 

As consequence of the insights gained, this work focuses on a new XVSM reference implementation (LinqSpace) with LINQ as primary interface for inquiry. For data storage any system which offers LINQ capabilities would be appropriate. In order to evaluate new opportunities an unconventional form of data storage regarding XVSM was chosen: the relational database.

 

Finally, the new LinqSpace is compared with XcoSpaces which allows illustrating the paradigm shift from "records" which are stored by the space toward direct interaction with a domain model. An example shows how the entities in an Entity-Relationship model and their relationships can be used as a basis for distributed coordination without additional adaptations.