MongoDB: Update an array using FindAndUpdate()

Question

I have this code

{
    "_id" : ObjectId("573308a2519d9ff8820e7be8"),
    "id" : "Example",
    "Test" : [ 
        "InsertB1",
        "InsertB2"
    ],
    "num" : 2
}

I would like to use the function findAndUpdate because I would like to

Change "InsertB1" to "UpdateB1"
increase the "num" from 2 to 3.

I've written this one, but does not work...

db.Collection.findAndModify({
    query: {
        id:"Example",
        num:{ $lt: 3 }
    },
    update: {
        id:"Example", 
        Test: "InsertB1",
         $set: { "Test.$": "Update1" },
         $inc: { num: 1 }
    },
    upsert:true,
    new:true
})

How can I modify my code?

because i want also to increase the "num" from 2 to 3 after that I have done the change... Do you think that i can use other strategy? — Valerio Sansone, May 11 '16 at 13:14
Do you need to return the modified document or the original document (document before modification)? — styvane, May 11 '16 at 14:00

Gerald Mücke · Accepted Answer · 2016-05-11T13:20:30.700

You forgot to include the array-element you'd like to update in the query. The $ refers to the first matching array element addressed in the query, if want to update "InsertB1", you have to add that.

Try use this

var oldDoc = db.Collection.findAndModify({
  query: {
    id:"Example", 
    num: {$lt:3}, 
    Test: "InsertB1"
  }, 
  update: {
    $set : {"Test.$": "Update1"}, 
    $inc: {num : 1 }}
 },
 upsert: true)

If returning the old (or new) document is not required, you may stick to the update command

db.Collection.update({
  id:"Example", 
  Test: "InsertB1",
  num: {$lt:3}
},{
  $set : { "Test.$": "Update1"}, 
  $inc: {num : 1}
})

MongoDB: Update an array using FindAndUpdate()

1 Answers1