Add ON CONSTRAINT support to conflict target, see elixir-ecto#2081

integration_test/cases/repo.exs

@@ -1198,6 +1198,20 @@ defmodule Ecto.Integration.RepoTest do
       assert c4.uuid != c1.uuid
     end
 
+    @tag :with_conflict_target
+    @tag :with_conflict_target_on_constraint
+    test "on conflict keyword list and conflict target on constraint" do
+      on_conflict = [set: [title: "new"]]
+      post = %Post{title: "old"}
+      {:ok, inserted} = TestRepo.insert(post, on_conflict: on_conflict, conflict_target: {:constraint, :posts_pkey})
+      assert inserted.id
+
+      {:ok, updated} = TestRepo.insert(%{post | id: inserted.id}, on_conflict: on_conflict, conflict_target: {:constraint, :posts_pkey})
+      assert updated.id == inserted.id
+      assert updated.title != "new"
+      assert TestRepo.get!(Post, inserted.id).title == "new"
+    end
+
     @tag :returning
     @tag :with_conflict_target
     test "on conflict keyword list and conflict target and returning and field source" do

lib/ecto/adapters/postgres/connection.ex

@@ -185,6 +185,8 @@ if Code.ensure_loaded?(Postgrex) do
     defp on_conflict({query, _, targets}, _header),
       do: [" ON CONFLICT ", conflict_target(targets), "DO " | update_all(query, "UPDATE SET ")]
 
+    defp conflict_target({:constraint, constraint}),
+      do: ["ON CONSTRAINT ", quote_name(constraint), ?\s]
     defp conflict_target([]),
       do: []
     defp conflict_target(targets),

lib/ecto/repo.ex

@@ -546,6 +546,8 @@ defmodule Ecto.Repo do
     * `:conflict_target` - Which columns to verify for conflicts. If
       none is specified, the conflict target is left up to the database
       and is usually made of primary keys and/or unique/exclusion constraints.
+      May also be `{:constraint, constraint_name_as_atom}` in databases
+      that support the "ON CONSTRAINT" expression.
 
   See the "Shared options" section at the module documentation for
   remaining options.
@@ -701,6 +703,8 @@ defmodule Ecto.Repo do
     * `:conflict_target` - Which columns to verify for conflicts. If
       none is specified, the conflict target is left up to the database
       and is usually made of primary keys and/or unique/exclusion constraints.
+      May also be `{:constraint, constraint_name_as_atom}` in databases
+      that support the "ON CONSTRAINT" expression.
 
   See the "Shared options" section at the module documentation.
 

lib/ecto/repo/schema.ex

@@ -455,6 +455,9 @@ defmodule Ecto.Repo.Schema do
     metadata(schema, prefix, source, autogen_id, context, opts)
   end
 
+  defp conflict_target({:constraint, constraint}, _dumper) when is_atom(constraint) do
+    {:constraint, constraint}
+  end
   defp conflict_target(conflict_target, dumper) do
     for target <- List.wrap(conflict_target) do
       case dumper do

test/ecto/adapters/postgres_test.exs

@@ -640,12 +640,14 @@ defmodule Ecto.Adapters.PostgresTest do
   end
 
   test "insert with on conflict" do
+    # For :nothing
     query = SQL.insert(nil, "schema", [:x, :y], [[:x, :y]], {:nothing, [], []}, [])
     assert query == ~s{INSERT INTO "schema" ("x","y") VALUES ($1,$2) ON CONFLICT DO NOTHING}
 
     query = SQL.insert(nil, "schema", [:x, :y], [[:x, :y]], {:nothing, [], [:x, :y]}, [])
     assert query == ~s{INSERT INTO "schema" ("x","y") VALUES ($1,$2) ON CONFLICT ("x","y") DO NOTHING}
 
+    # For :update
     update = from("schema", update: [set: [z: "foo"]]) |> normalize(:update_all)
     query = SQL.insert(nil, "schema", [:x, :y], [[:x, :y]], {update, [], [:x, :y]}, [:z])
     assert query == ~s{INSERT INTO "schema" AS s0 ("x","y") VALUES ($1,$2) ON CONFLICT ("x","y") DO UPDATE SET "z" = 'foo' RETURNING "z"}
@@ -660,6 +662,9 @@ defmodule Ecto.Adapters.PostgresTest do
 
     query = SQL.insert(nil, "schema", [:x, :y], [[:x, :y]], {:replace_all, [], []}, [])
     assert query == ~s{INSERT INTO "schema" ("x","y") VALUES ($1,$2) ON CONFLICT DO UPDATE SET "x" = EXCLUDED."x","y" = EXCLUDED."y"}
+
+    query = SQL.insert(nil, "schema", [:x, :y], [[:x, :y]], {:replace_all, [], {:constraint, :foo}}, [])
+    assert query == ~s{INSERT INTO "schema" ("x","y") VALUES ($1,$2) ON CONFLICT ON CONSTRAINT \"foo\" DO UPDATE SET "x" = EXCLUDED."x","y" = EXCLUDED."y"}
   end
 
   test "update" do