diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index b3a8e8bfe..c3c9cd983 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -136,10 +136,9 @@ model Valentine {
 
 model VoiceOnDemandMapping {
   userId    String @id @map("user_id") @db.VarChar
-  channelId String @map("channel_id") @db.VarChar
+  channelId String @unique @map("channel_id") @db.VarChar
   emoji     String @db.VarChar
 
-  @@unique([channelId], name: "IDX_VoiceOnDemandMapping_Unique_Channel")
   @@map(name: "voice_on_demand_mapping")
 }