To search the current topic map, please enter your tolog query in the box on the right, or select a query from this list of example queries:
Example queries: Resources that are both occurrences AND subjects
tolog is a topic map query language developed by Ontopia (and also supported by the Open Source topic map engine TM4J). It is inspired by Datalog and based around the concept of predicates (which map to associations, occurrences and other constructs in topic maps). Topics can be referenced in numerous ways, including by XML ID and by subject identifier.* The language also supports inferencing through the use of inference rules. For a full description, see The tolog Query Language Tutorial.
As of version 2.0 of the Ontopia Knowledge Suite (and version 007 of the Omnigator) tolog supports the complete Topic Maps Data Model (TMDM) ISO standard and is now an extremely powerful tool for querying every aspect of a topic map. Some of the new example queries supplied with the Omnigator demonstrate this very clearly. (Try for example the "English titles" query in opera.ltm, which finds operas that have base names in the scope "English".)
tolog also supports inference rules, which may be defined separately or embedded in the query itself. Refer to The tolog Query Language Tutorial for more details.
Ontopia is participating actively in the development of a standard Topic Maps Query Language (TMQL), which incorporates some features from tolog. Users of Ontopia's products will be provided with a migration path from tolog once TMQL has been defined and implemented.
* Note that, although subject identifiers are generally more robust than XML IDs (i.e., item identifiers), most of the example queries that are distributed with the Omnigator use the latter because they are easier to read.
