Inspired by http://github.com/MrHus/rql

What is mql

mql is clojure library to query map data structures

Usage

Given a map

(def m {:cid { :visits { :id-1 { :last-ts "1284166000040" :first-ts "1274166000000" :duration "40"} :id-2 { :last-ts "1274166000040" :first-ts "1274166000000" :duration "40"} :id-3 { :last-ts "1264166000040" :first-ts "1274166000000" :duration "40"}}

   :promo{
          :id-1 {:promo "p2"}
          :id-2 {:promo "p1"}}

   :purchase {
              :id-1
              {:order-id "order-id-1"
               :total-dollars "970.00"
               :purchase? "true",
               :merchant-total-dollars "1000.00"}
              :id-3
              {:order-id "order-id-2"
               :total-dollars "1000.00"
               :purchase? ""
               :merchant-total-dollars "1000.00"}}}})

Select: simple select

       (select [:cid :promo] m)  

will return

       {:id-1 {:promo "p2"} :id-2 {:promo "p1"}} 

Select: with filtering

      (select [:cid :purchase] (where [* :total-dollars] :gt 980) m) 

will return

      {:id-1
          {:order-id "order-id-1"
           :total-dollars "970.00"
           :purchase? "true",
           :merchant-total-dollars "1000.00"}}

You can use :gt, :lt, :ge, :le and :eq as logical operator in where clause. In where clause for key-seq you can use if a key is dynamic. The last key in where clause key-seq should not be .

Limitations:

• There could be only one * in Where Clause
• Select clause cannot have * now

License

Copyright (C) 2010 Siva Jagadeesan

Distributed under the Eclipse Public License, the same as Clojure.