diff --git a/prisma/migrations/20221012204442_change_relation/migration.sql b/prisma/migrations/20221012204442_change_relation/migration.sql
new file mode 100644
index 0000000..dc048b6
--- /dev/null
+++ b/prisma/migrations/20221012204442_change_relation/migration.sql
@@ -0,0 +1,31 @@
+/*
+  Warnings:
+
+  - The primary key for the `Booking` table will be changed. If it partially fails, the table could be left without primary key constraint.
+  - You are about to drop the column `billId` on the `Booking` table. All the data in the column will be lost.
+  - The `id` column on the `Booking` table would be dropped and recreated. This will lead to data loss if there is data in the column.
+  - A unique constraint covering the columns `[bookingId]` on the table `Bill` will be added. If there are existing duplicate values, this will fail.
+  - Added the required column `bookingId` to the `Bill` table without a default value. This is not possible if the table is not empty.
+
+*/
+-- DropForeignKey
+ALTER TABLE "Booking" DROP CONSTRAINT "Booking_billId_fkey";
+
+-- DropIndex
+DROP INDEX "Booking_billId_key";
+
+-- AlterTable
+ALTER TABLE "Bill" ADD COLUMN     "bookingId" INTEGER NOT NULL;
+
+-- AlterTable
+ALTER TABLE "Booking" DROP CONSTRAINT "Booking_pkey",
+DROP COLUMN "billId",
+DROP COLUMN "id",
+ADD COLUMN     "id" SERIAL NOT NULL,
+ADD CONSTRAINT "Booking_pkey" PRIMARY KEY ("id");
+
+-- CreateIndex
+CREATE UNIQUE INDEX "Bill_bookingId_key" ON "Bill"("bookingId");
+
+-- AddForeignKey
+ALTER TABLE "Bill" ADD CONSTRAINT "Bill_bookingId_fkey" FOREIGN KEY ("bookingId") REFERENCES "Booking"("id") ON DELETE RESTRICT ON UPDATE CASCADE;
diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index 526f0e9..321b5e7 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -29,7 +29,8 @@ model Bill {
   status          BillStatus        @default(UNINVOICED)
   tarif           Decimal
   additionalCosts AdditionalCosts[]
-  booking         Booking?
+  booking         Booking           @relation(fields: [bookingId], references: [id])
+  bookingId       Int               @unique
 }
 
 enum BookingStatus {
@@ -40,12 +41,11 @@ enum BookingStatus {
 }
 
 model Booking {
-  id              String        @id @default(uuid())
+  id              Int           @id @default(autoincrement())
   uuid            String        @unique @default(uuid())
   createdAt       DateTime      @default(now())
   updatedAt       DateTime      @updatedAt
-  bill            Bill?         @relation(fields: [billId], references: [id], onDelete: Cascade)
-  billId          Int?          @unique
+  bill            Bill?
   calendarEventId String?
   city            String
   destination     String