diff --git a/spec/ransack/adapters/active_record/base_spec.rb b/spec/ransack/adapters/active_record/base_spec.rb
index 4a0d5e7..bfa444e 100644
--- a/spec/ransack/adapters/active_record/base_spec.rb
+++ b/spec/ransack/adapters/active_record/base_spec.rb
@@ -18,6 +18,13 @@ module Ransack
             expect(subject.object).to be_an ::ActiveRecord::Relation
           end
 
+          context "multiple database connection" do
+            it "does not raise error" do
+              expect { Person.ransack(name_cont: "test") }.not_to raise_error
+              expect { SubDB::OperationHistory.ransack(people_id_eq: 1) }.not_to raise_error
+            end
+          end
+
           context 'with scopes' do
             before do
               allow(Person)
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index ebedf2a..ab3b430 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -37,6 +37,7 @@ RSpec.configure do |config|
     line = '=' * message.length
     puts line, message, line
     Schema.create
+    SubDB::Schema.create
   end
 
   config.before(:all)   { Sham.reset(:before_all) }
diff --git a/spec/support/schema.rb b/spec/support/schema.rb
index 88363d2..48f22ca 100644
--- a/spec/support/schema.rb
+++ b/spec/support/schema.rb
@@ -261,3 +261,30 @@ module Schema
     )
   end
 end
+
+module SubDB
+  class Base < ActiveRecord::Base
+    self.abstract_class = true
+    establish_connection(
+      adapter: 'sqlite3',
+      database: ':memory:'
+    )
+  end
+
+  class OperationHistory < Base
+  end
+
+  module Schema
+    def self.create
+      s = ::ActiveRecord::Schema.new
+      s.instance_variable_set(:@connection, SubDB::Base.connection)
+      s.verbose = false
+      s.define({}) do
+        create_table :operation_histories, force: true do |t|
+          t.string  :operation_type
+          t.integer :people_id
+        end
+      end
+    end
+  end
+end