SPARQL-DL Syntax

Our variant of the SPARQL-DL language is fully aligned to OWL 2.

Query Types

SPARQL-DL supports two different types of queries: ASK and SELECT. An ASK-query returns a Boolean result whereas a SELECT-query returns all possible bindings of the provided variables.

ASK-queries:

 ASK { [comma-separated list of atoms] }

SELECT-queries:

 SELECT [DISTINCT] [space-separated list of variables]
 [WHERE] { [comma-separated list of atoms] }
 [OR WHERE { [comma-separated list of atoms] }]* 

As within SPARQL, the DISTINCT keyword removes automatically all redundant bindings within the result set.

Primitives

In SPARQL-DL there are 3 different primitives for usage within query atoms: variables, URIs and literals. They have to follow the following syntax rules:

• Variable: ?[a-zA-Z]+ (for example ?a, ?myVar)
• Full IRI: <http://example.com>
• Prefixed IRI: [the prefix]:[the suffix]
• Literal: "this is a literal" (escape the character " inside a literal with \")

Prefixes

SPARQL-DL supports prefixes simmilar to those defined in SPARQL. Put the PREFIX definitions at the beginning of your SPARQL-DL-query:

 PREFIX [some prefix]: <[some URI]>
 PREFIX ...
 ...

OR WHERE

SPARQL-DL supports union-like statements called "OR WHERE". The results of the different where clauses are concatenated to one result.

 ...
 WHERE { ... }
 OR WHERE { ... }
 OR WHERE { ... }
 ...