#3 unsigned にしてみた

migration.py

@@ -28,7 +28,7 @@ def create_queries (
 ) -> None:
     with SCHEMA.create ('queries') as table:
         table.big_increments ('id')
-        table.big_integer ('user_id').nullable ().comment ('クエリ主')
+        table.big_integer ('user_id').unsigned ().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.string ('image_url').nullable ().default (None).comment ('添附画像 URL')
@@ -42,7 +42,7 @@ def create_answers (
 ) -> None:
     with SCHEMA.create ('answers') as table:
         table.big_increments ('id')
-        table.big_integer ('query_id').nullable ().comment ('クエリ')
+        table.big_integer ('query_id').unsigned ().nullable ().comment ('クエリ')
         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')
@@ -65,8 +65,8 @@ 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 ('query_id').unsigned ()
-        table.big_integer ('answer_id')
+        table.big_integer ('answer_id').unsigned ()
         table.unique (['query_id', 'answer_id'])