Hi, few notes from the top of my head on how we modeled this in the past:
User is a Node Resource (Document) is a Node Tag is a Node (having a label, language property, can be connected via relationships to other Tag Nodes representing its synonyms, can become a concept in (tree-)structured thesauri, etc...) Scenario: User U tags Resource R with Tag T: - Create special 'TaggingEvent' TE Node, with timestamp property and connect it to U, R and T by creating [TE, U], [TE, R] and [TE, T] relationships - TE nodes are indexed by timestamp, allowing to easily generate 'Tag activity streams' for different contexts - for users, resources or even tags (if it makes sense) - create some additional relationship(s) as needed between [U, T], [U, R] and [T, R] to simplify graph traversals and also to aggregate/cache the information like 'how many times was given R tagged with given T ~ this is f.e. expressed by some 'weight' property on the [T,R] relationship - and comes handy for generating things like tag clouds (~ get all [T,R] relationships with their weights) Scenario: User U bookmarks Resource R: - here it may be enough to create only [U,R] relationship with properties like timestamp, but we followed similar model as above - create special 'BookmarkEvent' Node BE, with timestamp and ralationships [BE, U] and [BE, R] and [U,R] - this again allows to easily create bookmarking activity streams, or to mix tagging+bookmarking events into one stream, if there is a requirement to do so. That's about it. Hope this helps. Regards, Josef. -- www.subject.cz ______________________________________________________________ > Od: "Max De Marzi Jr." <maxdema...@gmail.com> > Komu: Neo4j user discussions <user@lists.neo4j.org> > Datum: 09.06.2011 08:21 > Předmět: Re: [Neo4j] Design question: Del.icio.us > >Aseem, > >Which users tagged what? SELECT DISTINCT user_id FROM USER_TAGS WHERE >bookmark_id = x >Which bookmarks did a user tag? SELECT DISTINCT bookmark_id FROM >USER_TAGS WHERE user_id = x >Which bookmarks were tagged with x? SELECT DISTINCT bookmark_id FROM >USER_TAGS WHERE tag_id = x > >What question are you trying to answer that you can't get from a >relational table? > >I think it's better to make your model depending on the questions you >are trying to answer. > >I have a similar model (users tagging users) and I needed to answer: >Which users have been tagged by me or my network 6 degrees out? >What is the tagged distance a user is away from another user? > >Turns out, all I needed was User nodes with Tagged links. User -> >tagged -> User -> tagged -> User >Everything else I get from the relational db. > >When I start to care about which users have been tagged for by me or >my network 6 degrees out for this KEYWORD, then I'll create a more >complex model: >User -> UserKeyword -> tagged -> UserKeyword -> User > Keyword ---/ Keyword ---/ > >Regards, >Max > >On Thu, Jun 9, 2011 at 12:33 AM, Aseem Kishore <aseem.kish...@gmail.com> wrote: >> Also forgot to add: now if you want to show all links (globally) for a given >> tag, how do you do that? Are you indexing each tag-link (as a key-value >> pair) every time a tag is added? Removing from the index every time a tag is >> deleted? >> >> Thanks, >> >> Aseem >> >> On Wed, Jun 8, 2011 at 10:31 PM, Aseem Kishore >> <aseem.kish...@gmail.com>wrote: >> >>> I forgot to state this, but a key requirement of tags of course is that you >>> can apply multiple of them to the same link. >>> >>> Would you still go that route then? >>> >>> If you want to delete a link from your bookmarks, it's a matter then of >>> deleting each tag edge? >>> >>> Aseem >>> >>> >>> On Wed, Jun 8, 2011 at 10:28 PM, Siddhartha Kasivajhula < >>> countvajh...@gmail.com> wrote: >>> >>>> Couldn't you use edges for "tags" instead of nodes? >>>> >>>> user1 --tag--> link1 >>>> user2 --tag--> link1 >>>> user1 --tag--> link2 >>>> >>>> >>>> On Wed, Jun 8, 2011 at 10:23 PM, Aseem Kishore <aseem.kish...@gmail.com >>>> >wrote: >>>> >>>> > Hi guys, >>>> > >>>> > We're thinking about implementing tags in our system, and we're >>>> pondering a >>>> > few ideas for how we'd go about it, and none of them seem perfect. I'd >>>> like >>>> > to ask you guys: how would you design an analogous case: Del.icio.us? >>>> > >>>> > At the core, *users bookmark links*, so it makes sense to have "users" >>>> and >>>> > "links" as types of nodes, and "bookmark" as the type of edge that >>>> connects >>>> > them. Now, you can see all the links a given user has bookmarked, and >>>> all >>>> > the users that have bookmarked a given link. >>>> > >>>> > Now users can also *tag* links, of course, but the most interesting >>>> > requirement is that, when I'm looking at *my links*, I only want to see >>>> *my >>>> > tags*. Thus, tags can't be tied just to links; they have to be tied to >>>> > users >>>> > too. But most importantly, you have to maintain *which* user and *which* >>>> > link *each* tag is for. >>>> > >>>> > Thus, it seems most intuitive to us if we could have "tags" be nodes >>>> > that *point >>>> > to the "bookmark" edges*. Unfortunately, that's a hypergraph, which >>>> Neo4j >>>> > doesn't support. >>>> > >>>> > We could use intermediate nodes for bookmarks maybe, but that sort of >>>> sucks >>>> > to lose the intuitiveness of the graph and introduce redundant edges, >>>> more >>>> > complexity which makes consistency harder, etc. >>>> > >>>> > We have some other ideas, but I'm curious if any of you guys have >>>> thought >>>> > about this already or have done it, or if you guys have thoughts. Thanks >>>> in >>>> > advance! >>>> > >>>> > Aseem >>>> > _______________________________________________ >>>> > Neo4j mailing list >>>> > User@lists.neo4j.org >>>> > https://lists.neo4j.org/mailman/listinfo/user >>>> > >>>> _______________________________________________ >>>> Neo4j mailing list >>>> User@lists.neo4j.org >>>> https://lists.neo4j.org/mailman/listinfo/user >>>> >>> >>> >> _______________________________________________ >> Neo4j mailing list >> User@lists.neo4j.org >> https://lists.neo4j.org/mailman/listinfo/user >> >_______________________________________________ >Neo4j mailing list >User@lists.neo4j.org >https://lists.neo4j.org/mailman/listinfo/user > _______________________________________________ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
