models backed by views don't assume "id" columns are the primary key.

Closes #10247.

The same goes for tables with an "id" column but without primary key constraint.
Reading from the view works without configuration. If you have an updateable view
you need to use `self.primary_key = ''`.

1 files changed, 11 insertions, 0 deletions

diff --git a/activerecord/test/cases/view_test.rb b/activerecord/test/cases/view_test.rb
index 2f23d12de5..c2e71612a3 100644
--- a/activerecord/test/cases/view_test.rb
+++ b/activerecord/test/cases/view_test.rb
@@ -42,6 +42,13 @@ class ViewWithPrimaryKeyTest < ActiveRecord::TestCase
     assert_equal({"id" => 2, "name" => "Ruby for Rails", "status" => 0},
                  Ebook.first.attributes)
   end
+
+  def test_does_not_assume_id_column_as_primary_key
+    model = Class.new(ActiveRecord::Base) do
+      self.table_name = "ebooks"
+    end
+    assert_nil model.primary_key
+  end
 end
 
 class ViewWithoutPrimaryKeyTest < ActiveRecord::TestCase
@@ -80,5 +87,9 @@ class ViewWithoutPrimaryKeyTest < ActiveRecord::TestCase
     assert_equal({"name" => "Agile Web Development with Rails", "status" => 0},
                  Paperback.first.attributes)
   end
+
+  def test_does_not_have_a_primary_key
+    assert_nil Paperback.primary_key
+  end
 end
 end