CODEWITHSUNDEEP
node.jsexpressmongoose
sharsart
sharsart

Reputation: 228

Preventing duplicating entries with Mongoose and Node.Js

So I have a student grades object

[
  {
    _id: '5bf43c42a09e1129b8f0cd4c',
    user: '5bc89dec5f6e1103f808671b',
    StudentGrades: [
      {
        _id: '5bf43daf58f0f803d4e9760b',
        classCode: 'ENG1A0',
        gradeLevel: 12,
        credit: 1,
        mark: 67
      }
    ],
    __v: 0
  }
];

I use the following backend code to make entries into the database 

router.put('/:user_id', function(req, res) {
  let id = req.params.user_id;
  const gradeFields = {
    classCode: req.body.classCode,
    gradeLevel: req.body.gradeLevel,
    credit: req.body.credit,
    mark: req.body.mark
  };

  if (gradeFields)
    passport.authenticate('jwt', { session: false }),
      UserGrades.findOneAndUpdate(
        { user: id },
        { $push: { StudentGrades: gradeFields } },
        { new: true },
        { unique: true },
        function(err) {
          if (err) {
            res.send(err);
          } else {
            res.send(gradeFields);
          }
        }
      );
});

Everything is working but at this time, a person can have duplicate classes.

In the express code i tried using {unique: true} and tried setting the classCode mongoose model to unique as well, but it didn't work. Help would be appreciated

Upvotes: 1

Views: 68

Answers (1)

Will Garcia
Will Garcia

Reputation: 168

  1. Validate that the user_id maps to an existing user.
  2. Validate that this user does not already have a StudentGrade with the supplied classCode.
  3. Update the document and return the updated user.
router.put('/:user_id', async (req, res) => {
  const { user_id } = req.params;
  const gradeFields = {
    classCode: req.body.classCode,
    gradeLevel: req.body.gradeLevel,
    credit: req.body.credit,
    mark: req.body.mark
  };
  try {
    // Authenticate with Passport
    await passport.authenticate('jwt', { session: false });
    // Grab user with this user_id
    const existingUser = await UserGrades.findOne({ user: user_id });
    if(!existingUser) {
      // If user does not exist, throw 404
      res.status(404).send("User with this ID does not exist");
    }
    // Check if user has classCode already on an existing StudentGrade
    if(existingUser.StudentGrades.some(sg => sg.classCode === req.body.classCode)) {
      res.status(409).send("Student already has grade with this class code.");
    }
    // Update user record with new StudentGrade and return updates document
    const updatedUser = await UserGrades.findOneAndUpdate(
      { user: user_id },
      { $push: { StudentGrades: gradeFields } },
      { new: true }
    );
    res.status(200).send(updatedUser);
  } catch (e) {
    console.log('Failed to update user grades', e);
    // Unknown server error, send 500
    res.status(500).send(e)
  }
});

Upvotes: 1

Related Questions