diff --git a/packages/prisma/migrations/20230920124941_fix_documentmeta_relation/migration.sql b/packages/prisma/migrations/20230920124941_fix_documentmeta_relation/migration.sql
new file mode 100644
index 000000000..69b4591c5
--- /dev/null
+++ b/packages/prisma/migrations/20230920124941_fix_documentmeta_relation/migration.sql
@@ -0,0 +1,8 @@
+/*
+  Warnings:
+
+  - A unique constraint covering the columns `[documentMetaId]` on the table `Document` will be added. If there are existing duplicate values, this will fail.
+
+*/
+-- CreateIndex
+CREATE UNIQUE INDEX "Document_documentMetaId_key" ON "Document"("documentMetaId");
diff --git a/packages/prisma/schema.prisma b/packages/prisma/schema.prisma
index 675ac54d7..23fa8d2c7 100644
--- a/packages/prisma/schema.prisma
+++ b/packages/prisma/schema.prisma
@@ -117,6 +117,7 @@ model Document {
   DocumentMeta   DocumentMeta? @relation(fields: [documentMetaId], references: [id], onDelete: Cascade)
 
   @@unique([documentDataId])
+  @@unique([documentMetaId])
 }
 
 enum DocumentDataType {
@@ -134,10 +135,10 @@ model DocumentData {
 }
 
 model DocumentMeta {
-  id                 String     @id @default(cuid())
+  id                 String    @id @default(cuid())
   customEmailSubject String?
   customEmailBody    String?
-  Document           Document[]
+  Document           Document?
 }
 
 enum ReadStatus {