diff --git a/migration.py b/migration.py
index 2a32fa4..96cb65a 100644
--- a/migration.py
+++ b/migration.py
@@ -1,5 +1,8 @@
 from __future__ import annotations
 
+import os
+from typing import TypedDict
+
 from eloquent import DatabaseManager, Schema
 
 CONFIG: dict[str, DbConfig] = { 'mysql': { 'driver':    'mysql',
@@ -26,9 +29,10 @@ def create_queries (
         table.big_integer ('user_id').nullable ().comment ('クエリ主')
         table.integer ('target_character').comment ('クエリ先キャラクタ')
         table.text ('content').comment ('クエリ内容')
-        table.binary ('attachment').nullable ().default (None).comment ('添附')
+        table.string ('image_url').nullable ().default (None).comment ('添附画像 URL')
         table.integer ('query_type').comment ('クエリ区分')
-        table.datetime ('sent_at', 6).comment ('送信日時')
+        table.integer ('model').comment ('GPT のモデル')
+        table.datetime ('sent_at').comment ('送信日時')
         table.boolean ('answered').default (False).comment ('回答済')
 
 
@@ -40,7 +44,7 @@ def create_answers (
         table.integer ('character').comment ('キャラクタ区分')
         table.text ('content').comment ('回答内容')
         table.integer ('answer_type').comment ('回答区分')
-        table.datetime ('sent_at', 6).comment ('送信日時')
+        table.datetime ('sent_at').comment ('送信日時')
         table.boolean ('answered').default (False).comment ('回答済')
 
 
@@ -49,11 +53,19 @@ def create_users (
     with SCHEMA.create ('users') as table:
         table.big_increments ('id')
         table.integet ('platform').comment ('プラットフォーム区分')
-        table.string ('code').nullable ().comment ('ユーザ・コード（プラットフォーム依存）')
+        table.string ('code').comment ('ユーザ・コード（プラットフォーム依存）')
         table.string ('name').comment ('ユーザ名（プラットフォーム内）')
         table.binary ('icon').nullable ().comment ('アイコン')
 
 
+def create_query_answer_histories (
+) -> None:
+    with SCHEMA.create ('query_answer_histories') as table:
+        table.big_increments ('id')
+        table.big_integer ('query_id')
+        table.big_integer ('answer_id')
+
+
 class DbConfig (TypedDict):
     driver:     str
     host:       str