MongoDB - inserting/ updating a property inside an object inside an array inserts but also replaces-CodePudding

I want to update/insert a date into an object inside an array. I feel like I did everything as I was suppose to based on what I could find online but what happens is, that while I dont want to replace any properties inside my object, just add a property with value, it does gets replaced I have a n array of objects.

{
    'name': 'stationXYZ',
    'cancelledTrains': [
        {
            'info': 'infoinfoinfo',
        },
    ],
}

db.stations.updateOne({ name: 'stationXYZ' }, { $set: {cancelledTrains: {date: new Date("2022-02-14T15:49:00Z")} }})

that code inserts the date, however removes the info property. WHat am I doing wrong? Thanks!

CodePudding user response：

This is just how the update syntax works, you are telling Mongo to set the cancelledTrains field to the the { date: value } object.

You want to use the dot notation to access specific fields:

db.stations.updateOne({ name: 'stationXYZ' }, { $set: {"cancelledTrains.date": new Date("2022-02-14T15:49:00Z") }})