diff --git a/backend/src/db.js b/backend/src/db.js
index 8194299..d65ce7c 100644
--- a/backend/src/db.js
+++ b/backend/src/db.js
@@ -23,7 +23,7 @@ const migrations = [
       await conn.query(`
         CREATE TABLE users (
           id INT PRIMARY KEY AUTO_INCREMENT,
-          username VARCHAR(32) UNIQUE
+          username VARCHAR(32) NOT NULL UNIQUE
         )
       `);