Update if object prop doesn't exist in array

Question

I'd like to $push the variable content into the database content if the content.hash isn't already in the database. I don't want to store information again unnecessarily.

return shops.updateAsync({
  "user": user
}, {
  "$push": {
    "content": content
  }
})

I have a content object with the following params.

content = {
  "type": "csv",
  "name: "my-csv.csv",
  "content": csvContent,
  "date": new Date(),
  "hash": hash.digest('hex')
}

I don't want to ever insert the same CSV into the array. I'd like to ensure that there's only one by checking the hash, if there's a content object in the array with the hash it wouldn't upload or overwrite it.

Here's what I got so far, it's 3 requests :(

return users.findOneAsync({
  "user": user,
  "content.hash": content.hash,
}).then(function(exists){
  if(!exists) return false
  return users.updateAsync({
    "user": user
  }, {
    "$pull": { "content": { "hash": content.hash } },
  })
}
}).then(function(){
  return users.updateAsync({
    "user": user,
  }, {
    "$push": {"content": content}
  })
})

Your question is very vague, could you provide more information? — PBLC
– PBLC, Commented Jul 9, 2015 at 19:14
You wrote that you don't want to overwrite existing object if it's already present in content array, but in your code example you're overwriting it with new object. Which is the right behavior? — Leonid Beschastny
– Leonid Beschastny, Commented Jul 9, 2015 at 19:40
I want to overwrite / replace the existing one & I don't want duplicates. Sorry for the confusion. — ThomasReggi
– ThomasReggi, Commented Jul 9, 2015 at 20:46

Community · Accepted Answer · 2017-05-23 11:45:04Z

1

Not entirely sure what your data looks like, but I think it's very close to the answer I gave in another thread. TLDR; unique sub-documents.

https://stackoverflow.com/a/29102690/1058776

This comes up in google so I thought I'd add an alternative to using an index to achieve unique key constraint like functionality in subdocuments, hope that's OK.

I'm not terribly familiar with Mongoose so it's just a mongo console update:

var foo = { _id: 'some value' }; //Your new subdoc here

db.yourCollection.update(
{ '_id': 'your query here', 'myArray._id': { '$ne': foo._id } },
{ '$push': { myArray: { foo } })

With documents looking like:

{
  _id: '...',
  myArray: [{_id:'your schema here'}, {...}, ...]
}

The key being that you ensure update will not return a document to update (i.e. the find part) if your subdocument key already exists.

edited May 23, 2017 at 11:45

CommunityBot

11 silver badge

answered Aug 7, 2015 at 13:06

phuhgh

3033 silver badges10 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Update if object prop doesn't exist in array

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related