diff --git a/src/routes/api/v1/user.ts b/src/routes/api/v1/user.ts
index f8b8e14..14c2a0f 100644
--- a/src/routes/api/v1/user.ts
+++ b/src/routes/api/v1/user.ts
@@ -125,7 +125,7 @@ async function patch(req: Request, res: Response) {
 				},
 				data: {
 					name: value.name,
-					code: value.code
+					code: (value.code === '0000') ? null : value.code
 				},
 				select: {
 					id: true
diff --git a/src/routes/api/v1/user_schema.ts b/src/routes/api/v1/user_schema.ts
index 37e4427..868a6b2 100644
--- a/src/routes/api/v1/user_schema.ts
+++ b/src/routes/api/v1/user_schema.ts
@@ -22,7 +22,7 @@ const schema_get = validator
 // MARK: CREATE user
 const schema_post = validator.object({
 	name: validator.string().min(1).max(32).required(),
-	code: validator.string().min(4).max(4).trim().regex(new RegExp('/^[0-9]+$/'))
+	code: validator.string().min(4).max(4).trim().regex(new RegExp(/^[0-9]+$/))
 });
 
 // MARK: UPDATE user
@@ -30,7 +30,7 @@ const schema_patch = validator
 	.object({
 		id: validator.number().positive().precision(0).required(),
 		name: validator.string().min(1).max(32),
-		code: validator.string().min(4).max(4).trim().regex(new RegExp('/^[0-9]+$/'))
+		code: validator.string().min(4).max(4).trim().regex(new RegExp(/^[0-9]+$/))
 	})
 	.or('name', 'code');