Making Topicmaps SPARQL

Agenda
• Rationale
• SPARQL
• Theory
• Some examples

TMSparql
• A set of conventions and a small pseudo-
ontology to enable a topic map to present
itself as a SPARQL end-point

Rationale
• Integration
• A Simple Query Language

SPARQL
• A query language based on graph pattern
matching with support for value testing.
• The result of a SPARQL query is a list of
the different combination of variable-to-
term mappings that match against the
queried graph

Basic Matching
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
SELECT ?name ?mbox WHERE
{
?x foaf:name ?name .
?x foaf:mbox ?mbox
}

Filtering
PREFIX dc: <http://purl.org/dc/elements/1.1/>
PREFIX ns: <http://example.org/ns#>
SELECT ?title ?price WHERE
{
?x ns:price ?price .
FILTER (?price < 30.5)
?x dc:title ?title .
}

Optional Pattern Matching
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
SELECT ?name ?mbox WHERE
{
?x foaf:name ?name .
OPTIONAL { ?x foaf:mbox ?mbox }
}

Alternative Patterns
PREFIX dc10: <http://purl.org/dc/elements/1.0/>
PREFIX dc11: <http://purl.org/dc/elements/1.1/>
SELECT ?title WHERE
{
{ ?book dc10:title ?title } UNION { ?book
dc11:title ?title }
}

Goals
• Don’t get caught up in RDF <-> Topic Maps
conversion
• Make the result as intuitive and interoperable as
possible
– No extensions to the SPARQL syntax
– Limited use of “magic” identifiers
• Linked Data Query Interop
– Make it possible to fire the same queries at RDF-
based and Topic Maps-based SPARQL endpoints and
get equivalent results.

Resource Identifiers
• In RDF, every resource has a single URI
identifier.
• In Topic Maps topics in particular have
multiple identifiers.
• Solution:
– Any subject identifier can be used to refer to a
topic item.
– Any item identifier can be used to refer to a
topic map item

Basic Triple Patterns
• To make TMSparql intuitive and to make
SPARQL queries to Topic Maps equivalent
to RDF we introduce a number of basic
triple matching patterns.
• The intuitive nature of TMSparql comes
from being selective and restrictive about
how these patterns are defined.

Type-Instance Triple
• ?instance a ?type
• ?instance rdf:type ?type
– ?type identifies a topic item
– ?instance identifies a topic, association,
occurrence or role item that is an instance of
the topic identified by ?type

Examples
SELECT ?person {
?person a ont:person
}
Finds all instances of ont:person
SELECT ?type {
http://www.networkedplanet.com/ a ?type
}
Returns the topics that define the type(s) of the topic
with the subject or item identifier
http://www.networkedplanet.com.

Topic Property Triple
• ?topic ?type ?value
– ?topic bound to a topic item
– ?type bound to a topic item
– ?value bound to the value of an occurrence or
name of ?topic where the occurrence type is
defined by ?type

Examples
SELECT ?person, ?age {
?person a ont:person .
?person ont:age ?age
}
Finds all instances of ont:person that have
an ont:age occurrence and returns the
each matching person/age pair.

Examples
• The object part of the triple binds to a literal
value, so we can also make use of SPARQL
FILTER
SELECT ?person , ?age {
?person a ont:person .
?person ont:age ?age .
FILTER ( ?age >= 18 )
}
Find all people we can serve beer to

Related Topics Triple
• ?topic ?roleType ?relatedTopic
– Binds ?topic to any topic that plays a role of a type
other than the type bound to ?roleType in an
association
– Binds ?roleType to the type of role played by the
topic bound to ?relatedTopic
– Binds ?relatedTopic to any topic that plays a role
of the type bound to ?roleType
• Allows us to traverse an association using the
target role type as the predicate.

Example
SELECT ?person, ?company {
?person ont:employer ?company
}
Binds ?company to any topic that plays a
role of type ont:employer in an association
and binds ?person to the topic(s) that play
any other type of role in that association.

Aside: Mapping RDF Vocabularies
• Map RDF predicates that have a literal range to occurrence types.
• Map RDF predicates that have a resource range to role types (and
generate the association type and inverse role type).
E.g. If we have:
– foaf:name mapped to a name type and
– foaf:member mapped to a role type
Then the following query works against an RDF-based or TM-based
endpoint:
SELECT ?memberName, ?groupName {
?g foaf:member ?m .
?m foaf:name ?memberName .
?g foaf:name ?groupName
}

TMSparql Predicates
• The basic triple patterns introduced above provide
the ability to traverse from topic to topic and to
retrieve and filter on the properties of topics.
• For the occasions when a topic map practitioner
needs to get into more detail, we introduce a
number of predicates that perform different model
traversals.
• All TMSparql predicates use the namespace
http://www.networkedplanet.com/tmsparql
(mapped to tms: in the following examples)

TMSparql Predicates
• tms:reifier
– Traversal from a topic map item to its reifier.
• tms:topicProperty
– Traversal from a topic item to its name and occurrence items
• tms:value
– Traversal from a name or occurrence item to its value
• tms:role
– Traversal from an association item to its role items
• tms:player
– Traversal from a role item to the role player topic item
• tms:scope
– Traversal from a scoped topic map item to the topic items in its
scope.

Example
SELECT ?employmentAssoc, ?person, ?company,
?position {
?employmentAssoc a ont:worksFor .
?employmentAssoc tms:role ?r1 .
?r1 a ont:employee .
?r1 tms:player ?person .
?r2 a ont:employer .
?r2 tms:player ?company .
}
Finds all associations of type ont:worksFor with at least one role
of type ont:employee and one of type ont:employer and binds
the role players to ?person and ?company respectively.

Conclusion
• TMSparql is an implementation of the
SPARQL query language on top of the
TMDM.
• With careful mapping of ontologies, it is
possible to create a TMDM repository for
RDF data that responds to SPARQL queries
in the same way as a “native” RDF repository
would
• TMSparql makes it possible for TMDM
repositories to participate more fully in the
Linked Data web

Making Topicmaps SPARQL

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