Like Tim, I was thinking about the Datomic query language. Before you do
that though, remember that there's some basic relational algebra functions
in clojure.set <http://richhickey.github.io/clojure/clojure.set-api.html>.
Stuart Halloway demonstrates this in an interesting
gist<https://gist.github.com/stuarthalloway/3068749>.
It's working from a clojure.set baseline, from
here<http://www.lshift.net/blog/2010/08/21/some-relational-algebra-with-datatypes-in-clojure-12>.
Anyways, make the best choice for your needs. Here's an
example<https://gist.github.com/stuarthalloway/2645453>of Datomic
queries against regular Clojure collections.
HTH
Tim
On Wed, Jul 24, 2013 at 3:27 PM, Timothy Baldridge <tbaldri...@gmail.com>wrote:
> I think the first hint to an answer is found in your question. You are
> dealing with complex data, simplify the data, and querying the data is much
> simpler.
>
> For instance, if you have a tree, you could flatten the tree into a hash
> map like this:
>
> {parent-id {:children [child-id1 child-id2]}
> child-id1 {:children [child-id3 child-id4]}
> child-id2 ...}
>
> Now it's very simple to say things like "who are the parents of this child
> node?". Cedric is right, once you get a somewhat normalized data structure
> it's fairly trivial to query it with core.logic (using hash maps like the
> one above). You just have to write some code to get it into a format that
> core.logic can consume.
>
> *However, to be honest, this is where I reach for Datomic. It has a
> wicked fast query engine (datalog), you can run it in-memory (no disk
> access required), it has an excellent Clojure interface, the free version
> should do everything you need, and it has many many other features. For
> instance, given a child node in Datomic, you can find it's parents via:
> *
> (let [parents (:_children child-node)]
> ...)
>
> Not to mention that you can also create Datalog rules that allow you to
> create pre-defined queries that simplify your code quite a bit.
>
> In short, when I hear my self saying "find X where Y" or "I'd like to
> query this structure", I reach for Datomic, when that doesn't work for me
> (for whatever reason) then I start coding with core.logic.
>
> Timothy
>
>
>
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