Question 116740 in Mongodb Question posted in
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Mongodb change the type of all fields from string to int

I have imported a huge database from csv to mongodb.
It sadly imported every value as strings.
I have more then 1000 fields and 1M documents.
how can i change the type from ALL fieldvalues in ALL documents from string to int without doing it for every field manually?

Thanks for help.

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2

Answers


  1. 0

    I think you cannot change the datatype of all the fields in one go. You will have to do it field by field.

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  2. 0

    Well, if you don’t have nested documents, then this will work for you:

    db.collection.aggregate([
  {
    "$addFields": {
      "array": {
        "$map": {
          "input": {
            "$objectToArray": "$$ROOT"
          },
          "as": "item",
          "in": {
            k: "$$item.k",
            v: {
              "$convert": {
                "input": "$$item.v",
                "to": "int",
                "onError": "$$item.v",
                "onNull": "$$item.c"
              }
            }
          }
        }
      }
    }
  },
  {
    "$replaceRoot": {
      "newRoot": {
        "$arrayToObject": "$array"
      }
    }
  },
  {
    "$merge": {
      "into": "collection",
      "on": "_id",
      "whenMatched": "replace",
    }
  }
])

    In this, we first convert the document into an array, using $objectToArray.
    Then, we loop over the array and convert the values to int. Finally, we construct a new document from the array using $arrayToObject, and then we merge these new documents into the collection using $merge.

    Here’s the playground link.

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