Merge pull request #25620 from kamipo/create_without_primary_key

Pass `pk: false` to `connection.insert` explicitly if do not have a primary key

activerecord/lib/active_record/relation.rb

@@ -65,7 +65,7 @@ def insert(values) # :nodoc:
       @klass.connection.insert(
         im,
         'SQL',
-        primary_key,
+        primary_key || false,
         primary_key_value,
         nil,
         binds)

activerecord/test/cases/primary_keys_test.rb

@@ -174,6 +174,14 @@ def test_primary_key_update_with_custom_key_name
     assert_equal '2', dashboard.id
   end
 
+  def test_create_without_primary_key_no_extra_query
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = 'dashboards'
+    end
+    klass.create! # warmup schema cache
+    assert_queries(3, ignore_none: true) { klass.create! }
+  end
+
   if current_adapter?(:PostgreSQLAdapter)
     def test_serial_with_quoted_sequence_name
       column = MixedCaseMonkey.columns_hash[MixedCaseMonkey.primary_key]