diff --git a/DiscordDelete/DiscordContext.cs b/DiscordDelete/DiscordContext.cs
index 17e3086..85a7033 100644
--- a/DiscordDelete/DiscordContext.cs
+++ b/DiscordDelete/DiscordContext.cs
@@ -14,6 +14,12 @@ namespace DiscordDelete
 
         protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) =>
             optionsBuilder.UseSqlite($"Data Source={DataPath}");
+
+        protected override void OnModelCreating(ModelBuilder modelBuilder)
+        {
+            modelBuilder.Entity<Message>().HasIndex(m => m.MessageId).IsUnique(true);
+            base.OnModelCreating(modelBuilder);
+        }
     }
 
     public class Message