> It should be possible to randomly add and delete such relationships after
> indexWriter.addDocument(), is that the idea?
Yes. A "like" action may, for example allow me to tag an existing document by
connecting 2 documents - my personal "like" document and a document with
content of interest.
doc 1 = [user:mark tag:like]
doc 56 = [title:Lucene body:Lucene is a search library...]
I then call:
indexWriter.addLink(1,56)
If this was my first "Like" then I may need to contemplate using a variation of
the above API that allows a yet-to-be-committed "Document" object in place of
the doc ids.
> Adding such relationships by docId would need the addition of
> a separate (from the segments) index structure
Yes, I need to think about the detail of file structures next. For now I'm
sticking with thinking about user API and functionality and assuming we can
maintain cross-segment docid references that get updated somehow at merge time.
>
>
> Would each link also have an attribute (think payload)?
I was thinking if attributes are needed (e.g. a star rating on my document
"like" example) then this could be catered for with a document e.g. rather than
linking the single doc [user:mark tag:like] to all my liked docs I could create
specific doc instances of [user:mark rating:5 tag:like] and linking via that.
> Would such relationships be named (sth like foreign key field names)?
For now I was thinking of storing simple docid->docid links.
Once we have these links we could do some funky things:
{pseudo code:}
//My fave docs from last week
int myLikesDocId=searchForLuceneDocWithUserNameAndTag("mark", "like");
DocIdSet myLikedDocs =indexReader.getOutboundLinks(myLikesDocId)
searcher.search(lastWeekRangeQuery, new Filter(myLikedDocs));
//Other users who share my interests
DocIdSet usersWhoLikeWhatILike = indexReader.getInboundLinks(myLikedDocs);
Cheers
Mark
