Fixes #323 by allowing multiple column names

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Changes
 
+* 2.0.next in progress
+  * Fix #323 by supporting more than one SQL entity in `:on-conflict`.
+
 * 2.0.0-beta2 (for testing; 2021-04-13)
   * The documentation continues to be expanded and clarified in response to feedback!
   * Fix #322 by rewriting/simplifying `WHERE`/`HAVING` merge logic. **Important bug fix!**

doc/clause-reference.md

@@ -815,10 +815,11 @@ These are grouped together because they are handled
 as if they are separate clauses but they will appear
 in pairs: `ON ... DO ...`.
 
-`:on-conflict` accepts either a single SQL entity
-(a keyword or symbol), or a SQL clause, or a pair
-of a SQL entity and a SQL clause. The SQL entity is
-a column name and the SQL clause can be an
+`:on-conflict` accepts a sequence of zero or more
+SQL entities (keywords or symbols), optionally
+followed by a single SQL clause (hash map). It can also
+accept either a single SQL entity or a single SQL clause.
+The SQL entities are column names and the SQL clause can be an
 `:on-constraint` clause or a`:where` clause.
 
 _[For convenience of use with the `on-conflict` helper, this clause can also accept any of those arguments, wrapped in a sequence; it can also accept an empty sequence, and just produce `ON CONFLICT`, so that it can be combined with other clauses directly]_

src/honey/sql.cljc

@@ -589,26 +589,25 @@
     (into [(str (sql-kw k) " " (str/join ", " sqls))] params)))
 
 (defn- format-on-conflict [k x]
-  (cond (ident? x)
-        [(str (sql-kw k) " (" (format-entity x) ")")]
-        (map? x)
-        (let [[sql & params] (format-dsl x)]
-          (into [(str (sql-kw k) " " sql)] params))
-        (and (sequential? x)
-             (ident? (first x))
-             (map? (second x)))
-        (let [[sql & params] (format-dsl (second x))]
-          (into [(str (sql-kw k)
-                      " (" (format-entity (first x)) ") "
-                      sql)]
-                params))
-        (and (sequential? x) (= 1 (count x)))
-        (format-on-conflict k (first x))
-        (and (sequential? x) (= 0 (count x)))
-        [(sql-kw k)]
-        :else
-        (throw (ex-info "unsupported :on-conflict format"
-                        {:clause x}))))
+  (if (sequential? x)
+    (let [entities (take-while ident? x)
+          n (count entities)
+          [clause & more] (drop n x)
+          _ (when (or (seq more)
+                      (and clause (not (map? clause))))
+              (throw (ex-info "unsupported :on-conflict format"
+                              {:clause x})))
+          [sql & params] (when clause
+                           (format-dsl clause))]
+      (into [(str (sql-kw k)
+                  (when (pos? n)
+                    (str " ("
+                         (str/join ", " (map #'format-entity entities))
+                         ")"))
+                  (when sql
+                    (str " " sql)))]
+            params))
+    (format-on-conflict k [x])))
 
 (defn- format-do-update-set [k x]
   (cond (map? x)

src/honey/sql/helpers.cljc

@@ -768,10 +768,9 @@
   (generic-1 :values args))
 
 (defn on-conflict
-  "Accepts a single column name to detect conflicts
-  during an upsert, optionally followed by a `WHERE`
-  clause."
-  {:arglists '([column] [column where-clause])}
+  "Accepts zero or more SQL entities (keywords or symbols),
+  optionally followed by a single SQL clause (hash map)."
+  {:arglists '([column* where-clause])}
   [& args]
   (generic :on-conflict args))
 

test/honey/sql/postgres_test.cljc

@@ -72,6 +72,20 @@
                (on-conflict (on-constraint :distributors_pkey))
                do-nothing
                sql/format)))
+    (is (= ["INSERT INTO distributors (did, dname) VALUES (?, ?) ON CONFLICT (did) ON CONSTRAINT distributors_pkey DO NOTHING" 9 "Antwerp Design"]
+           ;; with both name and clause:
+           (-> (insert-into :distributors)
+               (values [{:did 9 :dname "Antwerp Design"}])
+               (on-conflict :did (on-constraint :distributors_pkey))
+               do-nothing
+               sql/format)))
+    (is (= ["INSERT INTO distributors (did, dname) VALUES (?, ?) ON CONFLICT (did, dname) ON CONSTRAINT distributors_pkey DO NOTHING" 9 "Antwerp Design"]
+           ;; with multiple names and a clause:
+           (-> (insert-into :distributors)
+               (values [{:did 9 :dname "Antwerp Design"}])
+               (on-conflict :did :dname (on-constraint :distributors_pkey))
+               do-nothing
+               sql/format)))
     (is (= ["INSERT INTO distributors (did, dname) VALUES (?, ?) ON CONFLICT ON CONSTRAINT distributors_pkey DO NOTHING" 9 "Antwerp Design"]
            ;; almost identical to nilenso version:
            (-> (insert-into :distributors)

test/honey/sql_test.cljc

@@ -618,6 +618,32 @@ INSERT INTO customers
 (name, email)
 VALUES ('Microsoft', 'hotline@microsoft.com')
 ON CONFLICT (name)
+DO NOTHING
+"]
+         (format {:insert-into :customers
+                  :columns [:name :email]
+                  :values [[[:inline "Microsoft"], [:inline "hotline@microsoft.com"]]]
+                  :on-conflict [:name]
+                  :do-nothing true}
+                 {:pretty true})))
+  (is (= ["
+INSERT INTO customers
+(name, email)
+VALUES ('Microsoft', 'hotline@microsoft.com')
+ON CONFLICT (name, email)
+DO NOTHING
+"]
+         (format {:insert-into :customers
+                  :columns [:name :email]
+                  :values [[[:inline "Microsoft"], [:inline "hotline@microsoft.com"]]]
+                  :on-conflict [:name :email]
+                  :do-nothing true}
+                 {:pretty true})))
+  (is (= ["
+INSERT INTO customers
+(name, email)
+VALUES ('Microsoft', 'hotline@microsoft.com')
+ON CONFLICT (name)
 DO UPDATE SET email = EXCLUDED.email || ';' || customers.email
 "]
          (format {:insert-into :customers