我如何在MongoDB中部分更新一个对象，以便新对象将覆盖/合并现有的一个

给定此文档保存在MongoDB中

{
   _id : ...,
   some_key: { 
        param1 : "val1",
        param2 : "val2",
        param3 : "val3"
   }
}

需要保存具有来自外部世界的关于param2和param3的新信息的对象

var new_info = {
    param2 : "val2_new",
    param3 : "val3_new"
};

我想在对象的现有状态上合并/覆盖新字段，这样param1就不会被删除

这样做

db.collection.update(  { _id:...} , { $set: { some_key : new_info  } }

将导致MongoDB完全按照要求执行，并将some_key设置为该值。更换旧的。

{
   _id : ...,
   some_key: { 
      param2 : "val2_new",
      param3 : "val3_new"
   }
}

如何让MongoDB只更新新字段(而不显式地逐个声明它们)?要得到这个:

{
   _id : ...,
   some_key: { 
        param1 : "val1",
        param2 : "val2_new",
        param3 : "val3_new"
   }
}

我正在使用Java客户端，但是任何示例都将受到欢迎

当前回答

我尝试了findmodify()来更新一个预先存在的对象中的特定字段。

https://docs.mongodb.com/manual/reference/method/db.collection.findAndModify/

2019-01-14 23:06:32

其他回答

使用$set执行此过程

.update({"_id": args.dashboardId, "viewData._id": widgetId}, {$set: {"viewData.$.widgetData": widgetDoc.widgetData}})
.exec()
.then(dashboardDoc => {
    return {
        result: dashboardDoc
    };
});

2017-02-03 12:19:15

db.collection.update(  { _id:...} , { $set: { some_key : new_info  } }

db.collection.update( { _id: ..} , { $set: { some_key: { param1: newValue} } } );

希望这对你有所帮助!

2019-11-23 03:44:10

使用包含必要的点路径的属性名创建一个更新对象。(“somekey。+来自OP的例子)，然后使用它进行更新。

//the modification that's requested
updateReq = { 
   param2 : "val2_new",
   param3 : "val3_new"   
}

//build a renamed version of the update request
var update = {};
for(var field in updateReq){
    update["somekey."+field] = updateReq[field];
}

//apply the update without modifying fields not originally in the update
db.collection.update({._id:...},{$set:update},{upsert:true},function(err,result){...});

2018-06-08 23:23:17

如果你想更新一个对象的多个字段，你可以试试这个:-

 let fieldsToUpdate = {};
 for (const key in allFields) {
 const fieldName = `flags.${key}`;   // define field as string literal
     fieldsToUpdate[fieldName] = allFields[key];
 }
 db.collection.updateOne(query, { $set: { ...fieldsToUpdate } } );

2021-11-23 15:08:57

从Mongo 4.2开始，db.collection.updateMany()(或db.collection.update())可以接受一个聚合管道，它允许使用聚合操作符，如$addFields，它输出输入文档中所有现有的字段和新添加的字段:

var new_info = { param2: "val2_new", param3: "val3_new" }

// { some_key: { param1: "val1", param2: "val2", param3: "val3" } }
// { some_key: { param1: "val1", param2: "val2"                 } }
db.collection.updateMany({}, [{ $addFields: { some_key: new_info } }])
// { some_key: { param1: "val1", param2: "val2_new", param3: "val3_new" } }
// { some_key: { param1: "val1", param2: "val2_new", param3: "val3_new" } }

The first part {} is the match query, filtering which documents to update (in this case all documents). The second part [{ $addFields: { some_key: new_info } }] is the update aggregation pipeline: Note the squared brackets signifying the use of an aggregation pipeline. Since this is an aggregation pipeline, we can use $addFields. $addFields performs exactly what you need: updating the object so that the new object will overlay / merge with the existing one: In this case, { param2: "val2_new", param3: "val3_new" } will be merged into the existing some_key by keeping param1 untouched and either add or replace both param2 and param3.

2019-06-14 19:35:43

我如何在MongoDB中部分更新一个对象，以便新对象将覆盖/合并现有的一个

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