unique制約追加

prisma/migrations/20240619063137_active_code_make_unique/migration.sql

@@ -0,0 +1,8 @@
+/*
+  Warnings:
+
+  - A unique constraint covering the columns `[code]` on the table `ActiveLoginCode` will be added. If there are existing duplicate values, this will fail.
+
+*/
+-- CreateIndex
+CREATE UNIQUE INDEX "ActiveLoginCode_code_key" ON "ActiveLoginCode"("code");

prisma/schema.prisma

@@ -76,7 +76,7 @@ model TaskChildLinkage {
 model ActiveLoginCode {
   id         String   @id @default(cuid())
   child_id   String
-  code       Int
+  code       Int      @unique
   created_at DateTime @default(now())
   child      Child    @relation(fields: [child_id], references: [id])
 }