如何在MongoDB中更新子文档数组？

要更新，请update()与$set一起使用。让我们创建一个包含文档的集合-

>db.demo134.insertOne({"EmployeeId":101,"EmployeeDetails":[{"EmployeeName":"Chris","EmployeeAge":27},{"EmployeeName":"Bob","EmployeeAge":28}]});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5e319b2f68e7f832db1a7f7c")
}
>db.demo134.insertOne({"EmployeeId":102,"EmployeeDetails":[{"EmployeeName":"David","EmployeeAge":24},{"EmployeeName":"Carol","EmployeeAge":29}]});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5e319b4468e7f832db1a7f7d")
}

在find()方法的帮助下显示集合中的所有文档-

> db.demo134.find().pretty();

这将产生以下输出-

{
   "_id" : ObjectId("5e319b2f68e7f832db1a7f7c"),
   "EmployeeId" : 101,
   "EmployeeDetails" : [
      {
         "EmployeeName" : "Chris",
         "EmployeeAge" : 27
      },
      {
         "EmployeeName" : "Bob",
         "EmployeeAge" : 28
      }
   ]
}
{
   "_id" : ObjectId("5e319b4468e7f832db1a7f7d"),
   "EmployeeId" : 102,
   "EmployeeDetails" : [
      {
         "EmployeeName" : "David",
         "EmployeeAge" : 24
      },
      {
         "EmployeeName" : "Carol",
         "EmployeeAge" : 29
      }
   ]
}

以下是更新MongoDB中子文档数组的查询-

> db.demo134.update(
...    {
...       "EmployeeId":101,
...       "EmployeeDetails.EmployeeName":"Chris"
...    },
...    {
...       $set: {
...          "EmployeeDetails.$.EmployeeName" : "Robert"
...       }
...    }
... );
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

在find()方法的帮助下显示集合中的所有文档-

> db.demo134.find().pretty();

这将产生以下输出-

{
   "_id" : ObjectId("5e319b2f68e7f832db1a7f7c"),
   "EmployeeId" : 101,
   "EmployeeDetails" : [
      {
         "EmployeeName" : "Robert",
         "EmployeeAge" : 27
      },
      {
         "EmployeeName" : "Bob",
         "EmployeeAge" : 28
      }
   ]
}
{
   "_id" : ObjectId("5e319b4468e7f832db1a7f7d"),
   "EmployeeId" : 102,
   "EmployeeDetails" : [
      {
         "EmployeeName" : "David",
         "EmployeeAge" : 24
      },
      {
         "EmployeeName" : "Carol",
         "EmployeeAge" : 29
      }
   ]
}