VIOS Dev — SPARQL FED Support
SPARQL has built-in support for blending data across libraries and data spaces. This support is encapsulated in the following SPARQL keywords:
- FROM — limits the scope of a the SPARQL query to the default (“unnamed”) libraries of one or more specified data spaces. The merge of the FROM list forms an ad-hoc data space for query execution
- FROM NAMED — limits the scope of a the SPARQL query to one or more specified libraries within the query’s data space
- SERVICE — declares the data space against which the corresponding WHERE triples are executed
- GRAPH — declares the library against which the corresponding WHERE triples are executed
VIOS App supports all four types of data source declaration and federation by the following features:
The Libraries option in the Show Me menu lists the libraries which contain the records in the record list of the Group By panel. Selecting a library by clicking the file cabinet restricts the query to records in that library:
In the current mPoC, only FROM NAMED is supported, and only one library can be selected. This will be extended in the PoC to include FROM name, and multiple selects for both.
SERVICE and GRAPH
For SERVICE and GRAPH, there are two system fields, Data Space and Library:
When a smart folder or record is added to the Data Space folder, the appropriate SERVICE clause is attached to the focus (and optionally its sub triples), where the parameter of the SERVICE clause is the selected smart folder or record. Similarly, when a smart folder or record is selected from the Library folder, the appropriate GRAPH clause is attached to the focus (and optionally its sub triples). The selector for the Data Space field is a VIOS data canvas with all known Data Spaces in focus (regardless of their relationship to the focus), and the selector for the Library field is a VIOS data canvas with all libraries in the current data space in focus (regardless of their relationship to the current focus). Thus, the Data Space field can be unbound. Likewise for the Library field.
Web Service Integration
An OSDB instance will be provided which returns semantic results from actions. These OSDB endpoints can then be used as Data Source field values. The VIOS Network beta will feature a terminal which provides the user access to OSDB actions registry and will facilitate the building of a OSDB smart folder via a simple to use form. The result is that users can federate data into the data canvas from a variety of non-RDF sources.
Note that the PoC will feature table view options which list all fields involved in the smart folder, so views like the following will be possible when the Data Space and/or Library fields are added to the breadcrumb path:
When a column header in the table is clicked, the corresponding breadcrumb in the breadcrumb path or facet collector is highlighted. A natural language description of the current Data Space location (from the root and including all nodes) accompanies the table view. Each node in the smart folder path is color-coded in the NLP description to match the color of the corresponding table header.