Update dependent Date field in Mongoose

Question

I have documents like this in Mongoose (MongoDb):

{
  begin: Date,
  end: Date
}

All I'd like to do is to:

Select all documents with end == null
and then update them using end = "begin increased by 10 days"

How can it be done within just a single update?

score 1 · Answer 1 · answered Sep 04 '13 at 14:44

1

This query selects all documents with end = null and update it with the new date Collection.update({end:null}, {$set: {end:'new_date'}},{ multi: true });

answered Sep 04 '13 at 14:44

Islam Ahmed

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`new_date` must be per document dependent, i.e. it's generally different in each updated document – Cartesius00 Sep 04 '13 at 14:54

score 1 · Accepted Answer · edited May 23 '17 at 12:21

Right now, you cannot reference a document's current properties in an update(). Instead, you'll have to iterate through the documents as described in this answer. In your case, it will look more like this:

db.docs.find({end:null}).forEach(
  function(doc) {
    doc.end = doc.begin + 10;
    db.docs.save(doc);
  }
)

This is the syntax for the Mongo shell-- you might have to make some changes for Mongoose, as per the API.

Update dependent Date field in Mongoose

2 Answers2