diff --git a/app/models/oauth2-authorization-code.js b/app/models/oauth2-authorization-code.js
index 40708a3..2017ea7 100644
--- a/app/models/oauth2-authorization-code.js
+++ b/app/models/oauth2-authorization-code.js
@@ -10,9 +10,9 @@ const Schema = mongoose.Schema;
 
 const OAuth2AuthorizationCodeSchema = new Schema({
   code: { type: String, required: true, index: 1 },
-  clientId: { type: Schema.ObjectId, required: true, index: 1 },
+  client: { type: Schema.ObjectId, required: true, index: 1, ref: 'OAuth2Client' },
   redirectUri: { type: String, required: true },
-  user: { type: Schema.ObjectId, required: true, index: 1 },
+  user: { type: Schema.ObjectId, required: true, index: 1, ref: 'User' },
   scopes: { type: [String], required: true },
 });