From b529cbe758e99368d3edb9d0fe2d368392e3ed86 Mon Sep 17 00:00:00 2001
From: Jumpei Matsuda <jmatsu.drm+github@gmail.com>
Date: Sat, 4 Sep 2021 07:01:45 +0900
Subject: [PATCH] Update optional relation's examples using optionalReferrersOn
 (#14)

Update optional relation's examples using optionalReferrersOn
---
 DAO.md | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/DAO.md b/DAO.md
index 801a1ee..a47e968 100644
--- a/DAO.md
+++ b/DAO.md
@@ -152,8 +152,17 @@ class UserRating(id: EntityID<Int>): IntEntity(id) {
     ...
 }
 ```
-Now `secondUser` will be a nullable field.
-Of course, you can still use `referrersOn`.
+Now `secondUser` will be a nullable field, and you should use `optionalReferrersOn` instead of `referrersOn` to get all the ratings for a `secondUser`.
+
+```kotlin
+class User(id: EntityID<Int>): IntEntity(id) {
+    companion object : IntEntityClass<User>(Users)
+    ...
+    val secondRatings by UserRating optionalReferrersOn UserRatings.secondUser // make sure to use val and optionalReferrersOn
+    ...
+}
+```
+
 ### many-to-many reference
 In some cases, a many-to-many reference may be required.
 Let's assume you want to add a reference to the following Actors table to the StarWarsFilm class: