Add support for timestamp

Author: kou

lib/activerecord_adbc_adapter/result.rb

@@ -35,7 +35,7 @@ def attach_model(model)
           when :datetime
             case field.data_type
             when Arrow::StringDataType
-              casted_type = Arrow::TimestampDataType.new(:micro)
+              casted_type = Arrow::TimestampDataType.new(:nano)
             end
           end
           if casted_type

lib/activerecord_adbc_adapter/schema_definitions.rb

@@ -1,4 +1,8 @@
 module ActiveRecordADBCAdapter
   class TableDefinition < ActiveRecord::ConnectionAdapters::TableDefinition
+    private
+    def aliased_types(name, fallback)
+      fallback
+    end
   end
 end

test/test_type.rb

@@ -181,7 +181,12 @@ def test_datetime_arrow
     end
     datetime = DateTime.new(2025, 7, 20, 20, 40, 23)
     User.create!(datetime: datetime)
-    array = Arrow::TimestampArray.new(:micro, [datetime.localtime])
+    if sqlite?
+      unit = :nano
+    else
+      unit = :micro
+    end
+    array = Arrow::TimestampArray.new(unit, [datetime.localtime])
     assert_equal(Arrow::Table.new(id: Arrow::Int64Array.new([1]),
                                   datetime: array),
                  User.to_arrow)
@@ -211,4 +216,31 @@ def test_time_arrow
                                   time: array),
                  User.to_arrow)
   end
+
+  def test_timestamp_active_record
+    ActiveRecord::Base.connection.create_table("users") do |table|
+      table.timestamp :timestamp
+    end
+    timestamp = Time.new(2025, 7, 20, 20, 40, 23)
+    User.create!(timestamp: timestamp)
+    assert_equal(User.new(id: 1, timestamp: timestamp),
+                 User.first)
+  end
+
+  def test_timestamp_arrow
+    ActiveRecord::Base.connection.create_table("users") do |table|
+      table.timestamp :timestamp
+    end
+    timestamp = Time.new(2025, 7, 20, 20, 40, 23)
+    User.create!(timestamp: timestamp)
+    if sqlite?
+      unit = :nano
+    else
+      unit = :micro
+    end
+    array = Arrow::TimestampArray.new(unit, [timestamp])
+    assert_equal(Arrow::Table.new(id: Arrow::Int64Array.new([1]),
+                                  timestamp: array),
+                 User.to_arrow)
+  end
 end