diff --git a/migration.py b/migration.py
index 615d5f2..8849e01 100644
--- a/migration.py
+++ b/migration.py
@@ -21,7 +21,6 @@ def main (
     create_answers ()
     create_users ()
     create_query_answer_histories ()
-    add_constraints_to_answers ()
     add_constraints_to_query_answer_histories ()
 
 
@@ -51,12 +50,6 @@ def create_answers (
         table.boolean ('answered').default (False).comment ('回答済')
 
 
-def add_constraints_to_answers (
-) -> None:
-    with SCHEMA.table ('answers') as table:
-        table.foreign ('query_id').references ('id').on ('queries').on_update ('cascade').on_delete ('restrict')
-
-
 def create_users (
 ) -> None:
     with SCHEMA.create ('users') as table: