如何在MongoDB中更新子对象？
要更新子对象，请使用$set运算符。让我们首先用文档创建一个集合-
>db.updateChildObjectsDemo.insertOne({"StudentName":"Chris","StudentOtherDetails":{"StudentSubject":"MongoDB","StudentCountryName":"AUS"}});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ce964e078f00858fb12e91f")
}以下是在find()方法的帮助下显示集合中所有文档的查询-
> db.updateChildObjectsDemo.find().pretty();
这将产生以下输出-
{
"_id" : ObjectId("5ce964e078f00858fb12e91f"),
"StudentName" : "Chris",
"StudentOtherDetails" : {
"StudentSubject" : "MongoDB",
"StudentCountryName" : "AUS"
}
}以下是更新MongoDB中子对象的查询-
> db.updateChildObjectsDemo.update({"StudentName" : "Chris"},{$set:{"StudentOtherDetails.StudentCountryName":"UK"}});
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })让我们再次检查文档-
> db.updateChildObjectsDemo.find().pretty();
这将产生以下输出-
{
"_id" : ObjectId("5ce964e078f00858fb12e91f"),
"StudentName" : "Chris",
"StudentOtherDetails" : {
"StudentSubject" : "MongoDB",
"StudentCountryName" : "UK"
}
}