How to pass an empty string as value of a field in dynamodb?

Question

I am trying to do a post request with the following json data. But i need one field ie 'notes' to pass as an empty string value. When I am passing like that, an error is getting :

'One or more parameter values were invalid: An AttributeValue may not contain an empty string'.

How can I fix this issue?

//json data which i need to post
  {
  "storeId": "106",
  "addressId": "1",
  "managerId": "1",
  "name": "Syammohan",
  "contactNo": "9656985685",
  "notes": "",
  "bookingType": "Weddding Consult",
  "bookingDate": "2019-05-02",
  "bookingTime": "09:00 am"
}

function bookingDone(employee) {
  var {

    storeId,
    addressId,
    managerId,
    name,
    contactNo,
    notes,
    bookingType,
    bookingStatus,
    bookingTime
  } = req.body

  console.log("notes", notes);

  const params = {
    TableName: "Booking",

    Item: {
      id: id,
      storeId: storeId,
      addressId: addressId,
      managerId: managerId,
      name: name,
      contactNo: contactNo,
      notes: notes,
      bookingType: bookingType,
      bookingStatus: bookingStatus,
      bookingDate: bookingDate,
      bookingTime: bookingTime,
      employeeId: employee.id

    },

  };

  docClient.put(params, (error) => {
    if (error) {
      console.log(error);
      res.status(400).json({ error: 'Could not create booking' });
    }
    // queue.push(JSON.stringify({ event: 'booking.booking.created', model: { 'Bookings': params.Item } }));
    res.send(params.Item)
    // res.json({ id, name, info });

  });
}

dynamo doesn't accept empty string, why not put some generic string or leave the field altogether? — 1565986223, May 02 '19 at 06:48
Your problem is not NodeJS related. Can't you set `"notes": null`? — Marnix Harderwijk, May 02 '19 at 06:49
From docs `Attribute values cannot be null. String and Binary type attributes must have lengths greater than zero.` — 1565986223, May 02 '19 at 06:53
As of June 2020, DynamoDB now supports empty strings natively. Make sure to turn off `convertEmptyValues` or else empty strings will be converted to NULL. https://stackoverflow.com/a/62166912/1457398 — Aaron_H, Jun 03 '20 at 06:57

liza · Accepted Answer · 2019-05-03T11:41:50.847

13

Yes Dynamodb cannot accepts empty string. So edit the aws configuration

var docClient = new AWS.DynamoDB.DocumentClient({ convertEmptyValues: true });

This works!

edited May 03 '19 at 11:41

answered May 02 '19 at 06:58

liza

484
2
6
21

5

Dynamo supports empty strings starting May 2020: https://aws.amazon.com/about-aws/whats-new/2020/05/amazon-dynamodb-now-supports-empty-values-for-non-key-string-and-binary-attributes-in-dynamodb-tables/ – goldfrapp04 Jun 11 '20 at 00:07

score 7 · Answer 2 · answered May 02 '19 at 07:00

A map of attributes and their values. Each entry in this map consists of an attribute name and an attribute value. Attribute values must not be null; string and binary type attributes must have lengths greater than zero; and set type attributes must not be empty. Requests that contain empty values will be rejected with a ValidationException exception.

You can solve the problem by defining a function to remove empty string from the object like

function removeEmptyStringElements(obj) {
  for (var prop in obj) {
    if(obj[prop] === '') {// delete elements that are empty strings
      delete obj[prop];
    }
  }
  return obj;
}
removeEmptyStringElements(req.body);

This will remove the empty attributes from your object.

If your object contains nested object then use the following function

function removeEmptyStringElements(obj) {
  for (var prop in obj) {
    if (typeof obj[prop] === 'object') {// dive deeper in
      removeEmptyStringElements(obj[prop]);
    } else if(obj[prop] === '') {// delete elements that are empty strings
      delete obj[prop];
    }
  }

removeEmptyStringElements(req.body)

score 6 · Answer 3 · answered May 20 '20 at 09:44

6

Amazon DynamoDB now supports empty values for non-key String and Binary attributes in DynamoDB tables https://stackoverflow.com/a/61909830/7532347

answered May 20 '20 at 09:44

kev

79
1
1

Thanks for the link! Does the user need to update anything? I'm still getting the ValidationException error when I pass null to an optional – João Pereira Jun 11 '20 at 14:51
This repeats the identical update [answer](https://stackoverflow.com/a/61880991/1357094) – cellepo Jul 03 '20 at 21:57

score 4 · Answer 4 · answered May 19 '20 at 00:04

4

Empty values in non-key string/binary attributes is now supported - AWS announcement

answered May 19 '20 at 00:04

rtyqwe

41
1

How to pass an empty string as value of a field in dynamodb?

4 Answers4