This document discusses an update language for topic maps based on tolog. The language allows users to insert, delete, merge, and update data in a topic map using concise statements. The update language builds on an existing tolog implementation and provides architectural benefits like enabling a JDBC-like API and easy network access. Some open questions remain around expressiveness, handling missing values, and supporting rules/templates within updates. The language has been implemented and tested but requires documentation and real-world use before being released to users.

1. tolog updates TMRA 2009, November 12, Leipzig Lars Marius Garshol, <larsga@bouvet.no>

2. Why an update language? Easier to use than the API empowers new groups of users Potentially better performance than the API Can be embedded in various DSLs Architectural benefits enables JDBC-like API easily accessible over the network

3. Why one based on tolog? TMQL was not ready at the time in fact, it still isn’t We have a tolog implementation implementing the query part is the biggest job So tolog was the pragmatic choice

4. What it contains INSERT: add new data to topic map using CTM DELETE: remove data from topic map MERGE: merge objects UPDATE: change existing values

5. The language

6. DELETE Static form delete lmg Dynamic form delete $person from instance-of($person, person)

7. Deletion effects Deleting topic removes from scope from topic types objects typed with as reifier Topic map Topic Name Variant Occurrence Association Role

8. Delete functions Used for removing values from set properties delete subject-identifier(topic, “http://ex.org/tst”) delete item-identifier(topic, “file://...#tst”) delete subject-locator(topic, “http://ex.org”) Other functions scope($statement, $topic) reifies($reified, $reifier) direct-instance-of($topic, $type)

9. MERGE Static form MERGE topic1, topic2 Dynamic form MERGE $p1, $p2 FROM instance-of($p1, person), instance-of($p2, person), email($p1, $email), email($p2, $email)

10. INSERT Static form INSERT lmg isa person; - “Lars Marius Garshol” . Dynamic form INSERT tmcl:belongs-to-schema(tmcl:container : $s, tmcl:containee: $c) FROM instance-of($c, tmcl:constraint)

11. Another INSERT example INSERT $topic $psi . FROM instance-of($topic, $type), instance-of($type, psi-type), topic-name($topic, $name), value($name, $value), str:translate($value, $token, ..., ...), str:concat($psi, “http://psi.example.org/...”)

12. Yet another INSERT event-in-year(event: $e, year: $y) FROM start-date($e, $date), str:substring($y, $date, 4)

13. Ugliness with INSERT Other statements can use %parameter% syntax in INSERT this is not possible in the CTM part have to say FROM $a = %a% to translate May need to project away variables used in query but not in CTM right now this is done via an implicit projection not clear whether this will confuse users or not

14. UPDATE Static form UPDATE value(@3421, “New name”) Dynamic form UPDATE value($TN, “Ontopia”) FROM topic-name(oks, $TN)

15. The UPDATE functions value($object, $string) works on topic name, variant, occurrence resource($object, $string) works on variant and occurrence

16. Considerations

17. New API Old API has QueryProcessorIF methods QueryResultIF execute(String) ParsedQueryIF parse(String) New API adds int update(String) ParsedModificationStatementIF parseUpdate(String) also adds ParsedStatementIF as common interface

18. New access methods Omnigator query plug-in being extended to support updates TMRAP web service being extended with a tolog-update request

19. A scripting language? Considering to make a language supporting batches of statements that is, running series of modification statements perhaps also setting variables Not clear what features are needed for loops? if? etc

20. Implementation Mostly straightforward... new classes to represent parsed versions of new statements all reference the class for SELECT statements for their FROM subqueries ...except CTM parsing requires two different Antlr parsers (CTM & tolog) had to split the query string in advance, then pass different pieces to different parsers

21. Concerns Is it expressive enough? just about any modification can be expressed however, it might require many statements Do INSERT statements need “if”? to handle missing values, for example Rules and templates currently, these cannot be defined in modification statements is that a bug? or a feature?

22. Current status All four statement types implementated Test suite added Some minor nits still need sorting out

23. Future work Start using the language Write documentation! Hand it over to users See how it goes