Hy, I'm new in nodeJS. I am stuck at updating a single entity of document. I'm updating the whole document easily but can't able to update a single value. code

router.patch("/:id", async (req, res) => {
  console.log(req.params.id);
  // check valid student
  let student = await Student.findById(req.params.id);
  if (!student) return res.status(400).send("Student Not Found");

  // validition
  // const { error } = validate(req.body);
  // if (error) return res.status(400).send(error.details[0].message);

  // update the student
  student = await Student.updateOne({_id:req.params.id},{$set: req.body});
  if(!student) return res.status(404).send('The student record not Updated')
  res.status(200).send('Student Record Updated')
});

Validation Function

function validateStudent(student){
    const schema = Joi.object({
        name:Joi.string().min(3).max(50).required(),
        fatherName:Joi.string().min(3).max(50).required(),
        email:Joi.string().min(5).max(50).required().email(),
        class:Joi.number().min(9).max(12).required(),
        fee:Joi.number().min(4000).max(10000).required(),
        address:Joi.string().min(1).max(255).required(),
        phone:Joi.string().min(1).max(255).required(),
    })
    return schema.validate(student)
}

Now It's updating my single value in DB but without validation, because if I uncomment the validation then it forces for all required field. How I can validate and update a single value which coming in API from the frontend?