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Handle non-where-generating bindings.

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This commit is contained in:
Richard Newman 2016-07-12 18:46:46 -07:00
parent 0832396071
commit 0149bdcd77
1 changed files with 12 additions and 10 deletions
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22
src/datomish/query.cljc
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@ -83,12 +83,13 @@
TODO: experiment; it might be the case that producing more
pairwise equalities we get better or worse performance."
[bindings]
(cons :and
(mapcat (fn [[k vs]]
(when (> (count vs) 1)
(let [root (first vs)]
(map (fn [v] [:= root v]) (rest vs)))))
bindings)))
(let [clauses (mapcat (fn [[_ vs]]
(when (> (count vs) 1)
(let [root (first vs)]
(map (fn [v] [:= root v]) (rest vs)))))
bindings)]
(when-not (empty? clauses)
(cons :and clauses))))
(defn patterns->body [patterns]
(let [clauses
@ -140,15 +141,16 @@
(let [{:keys [from where bindings]} ; 'where' here is SQL.
(patterns->body where) ; 'where' here is the Datalog :where clause.
variable-lookup #(or (first (%1 bindings))
(raise (str "Couldn't find variable " %1)))]
(raise (str "Couldn't find variable " %1)))
where-from-bindings (bindings->where bindings)]
;; Now we expand the :where clause to also include any
;; repeated variable usage, as noted in `bindings`.
{:select (elements->sql-projection (:elements find) variable-lookup)
:from from
:where (list :and
where
(bindings->where bindings))})))
:where (if where-from-bindings
(list :and where where-from-bindings)
where)})))
(defn find->sql-string
"Take a parsed `find` expression and turn it into SQL."