diff --git a/update_db.py b/update_db.py
index 168be1e..b83127d 100644
--- a/update_db.py
+++ b/update_db.py
@@ -172,6 +172,42 @@ class VideoDao:
                 videos.append (self._create_dto_from_row (row, with_relation_tables))
             return videos
 
+    def upsert_all (
+            self,
+            videos:                 list[VideoDto],
+            with_relation_tables:   bool            = True,
+    ) -> int:
+        with self.conn.cursor () as c:
+            for video in videos:
+                c.execute ("""
+                        INSERT INTO
+                          videos(
+                            code,
+                            title,
+                            description,
+                            uploaded_at,
+                            deleted_at)
+                        VALUES
+                          (
+                            %s,
+                            %s,
+                            %s,
+                            %s,
+                            %s)
+                        ON DUPLICATE KEY UPDATE
+                          code = VALUES(code),
+                          title = VALUES(title),
+                          description = VALUES(description),
+                          uploaded_at = VALUES(uploaded_at),
+                          deleted_at = VALUES(deleted_at)""", (
+                               video.code,
+                               video.title,
+                               video.description,
+                               video.uploaded_at,
+                               video.deleted_at))
+                video.id_ = c.lastrowid
+                # TODO: with_relation_tables が True の場合，子テーブルも UPSERT すること
+
     def _create_dto_from_row (
             self,
             row,