Error when increasing value by other field

[Amit_Hadad]

Im trying to update object in schema by other object. somthing like this:

Resources: {
Gold: Number
}
Workers: {
Efficiency: 
{
     Mine: Number
}
}

  signUpTemplate.updateMany({},

    { $inc:

        {"Resources.Gold": "Workers.Efficiency.Mine"}

    }, function(err, response){

        if(err) console.log(err);

        else console.log(response);

    });

Im getting a type cast error since the Workers.Efficienct.Mine is not getting recognized as an object so it count as String.

[Tarun_Gaur]

Hello @Amit_Hadad ,

Welcome to The MongoDB Community Forums!

Could you please provide below details for me to understand your use-case further?

• Some sample documents
• Expected output/Expected updated documents after query is executed successfully
• Error that you are getting
• MongoDB version
• Driver version

Regards,
Tarun

[steevej (Steeve Juneau)]

I do not know if there is another way but you could use update with aggregation pipeline.

Something like this untested code:

c.updateMany( {} ,
  [
    { "$set" : {
      "Resources.Gold" : { $add : ["$Resources.Gold","$Workers.Efficiency.Mine"]}
    }}
  ]
)