diff --git a/src/main/resources/mapper/PostRatingMapper.xml b/src/main/resources/mapper/PostRatingMapper.xml
new file mode 100644
index 0000000..097eeb8
--- /dev/null
+++ b/src/main/resources/mapper/PostRatingMapper.xml
@@ -0,0 +1,5 @@
+<insert id="insertOrUpdate">
+    INSERT INTO post_ratings (user_id, post_id, rating)
+    VALUES (#{userId}, #{postId}, #{rating})
+    ON DUPLICATE KEY UPDATE rating = VALUES(rating)
+</insert>
\ No newline at end of file