diff --git a/src/main/resources/db/migration/mariadb/V250__maimai2_item_integrity.sql b/src/main/resources/db/migration/mariadb/V250__maimai2_item_integrity.sql
new file mode 100644
index 00000000..6fe387b4
--- /dev/null
+++ b/src/main/resources/db/migration/mariadb/V250__maimai2_item_integrity.sql
@@ -0,0 +1,4 @@
+# Fixes crashes due to duplicate keys in maimai2_user_item
+alter table maimai2_user_item
+    add constraint maimai2_user_item_pk
+        unique (item_kind, item_id, user_id);
diff --git a/src/main/resources/db/migration/mysql/V250__maimai2_item_integrity.sql b/src/main/resources/db/migration/mysql/V250__maimai2_item_integrity.sql
new file mode 100644
index 00000000..6fe387b4
--- /dev/null
+++ b/src/main/resources/db/migration/mysql/V250__maimai2_item_integrity.sql
@@ -0,0 +1,4 @@
+# Fixes crashes due to duplicate keys in maimai2_user_item
+alter table maimai2_user_item
+    add constraint maimai2_user_item_pk
+        unique (item_kind, item_id, user_id);
diff --git a/src/main/resources/db/migration/sqlite/V250__maimai2_item_integrity.sql b/src/main/resources/db/migration/sqlite/V250__maimai2_item_integrity.sql
new file mode 100644
index 00000000..324c57e5
--- /dev/null
+++ b/src/main/resources/db/migration/sqlite/V250__maimai2_item_integrity.sql
@@ -0,0 +1 @@
+CREATE UNIQUE INDEX maimai2_user_item_pk ON maimai2_user_item(item_kind, item_id, user_id);