1 files changed, 25 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 95beeb4cae..5919801519 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -196,6 +196,17 @@ module ActiveRecord
         true
       end
 
+      def supports_insert_returning?
+        true
+      end
+
+      def supports_insert_on_conflict?
+        postgresql_version >= 90500
+      end
+      alias supports_insert_on_duplicate_skip? supports_insert_on_conflict?
+      alias supports_insert_on_duplicate_update? supports_insert_on_conflict?
+      alias supports_insert_conflict_target? supports_insert_on_conflict?
+
       def index_algorithms
         { concurrently: "CONCURRENTLY" }
       end
@@ -425,6 +436,20 @@ module ActiveRecord
         index.using == :btree || super
       end
 
+      def build_insert_sql(insert) # :nodoc:
+        sql = +"INSERT #{insert.into} #{insert.values_list}"
+
+        if insert.skip_duplicates?
+          sql << " ON CONFLICT #{insert.conflict_target} DO NOTHING"
+        elsif insert.update_duplicates?
+          sql << " ON CONFLICT #{insert.conflict_target} DO UPDATE SET "
+          sql << insert.updatable_columns.map { |column| "#{column}=excluded.#{column}" }.join(",")
+        end
+
+        sql << " RETURNING #{insert.returning}" if insert.returning
+        sql
+      end
+
       private
         def check_version
           if postgresql_version < 90300