如何使用Mongoose删除对象内的子文档

Question

我正在尝试使用Mongoose从Object中删除带有ID的子文档.我试图在Moongose中使用update fucntion但是在我运行脚本后我得到状态"Ok:1"但状态"nModified:0".试图使用以下脚本:

 Page.update({"subPages._id": req.body.ID}, {"$unset":{"subPages":1}}, function (re,q) {
    console.log(q);
});

此脚本从对象中删除所有子文档.这是我的json:

{
"_id" : ObjectId("585a7a7c2ec07b40ecb093d6"),
"name_en" : "Head Page",
"name_nl" : "Head Page",
"slug_en" : "Head-page",
"slug_nl" : "hoofd-menu",
"content_en" : "<p>Easy (and free!) You should check out our premium features.</p>",
"content_nl" : "<p>Easy (and free!) You should check out our premium features.</p>",
"date" : ISODate("2016-12-21T12:50:04.374Z"),
"is_footerMenu" : 0,
"is_headMenu" : 0,
"visible" : 1,
"__v" : 0,
"subPages" : [ 
    {
        "content_nl" : "<p>Easy (and free!) You should check out our premium features.</p>",
        "content_en" : "<p>Easy (and free!) You should check out our premium features.</p>",
        "slug_nl" : "Sub-page",
        "slug_en" : "Sub-page",
        "name_nl" : "Subpage",
        "name_en" : "Subpage",
        "date" : ISODate("2016-12-21T14:58:44.733Z"),
        "subPages" : [],
        "is_footerMenu" : 0,
        "is_headMenu" : 0,
        "visible" : 1,
        "_id" : ObjectId("585a98a46f657b52489087a8")
    }, 
    {
        "content_nl" : "<p>Easy (and free!) You should check out our premium features.</p>",
        "content_en" : "<p>Easy (and free!) You should check out our premium features.</p>",
        "slug_nl" : "Subpage",
        "slug_en" : "Subpage",
        "name_nl" : "Subpage1",
        "name_en" : "Subpage1",
        "date" : ISODate("2016-12-21T14:58:54.819Z"),
        "subPages" : [],
        "is_footerMenu" : 0,
        "is_headMenu" : 0,
        "visible" : 1,
        "_id" : ObjectId("585a98ae6f657b52489087a9")
    }
]

}

我想删除带ID的子对象

585a98a46f657b52489087a8

我该怎么做？

Answer 1

为了从数组中删除元素（子文档），您需要$pull它。

Page.update({
  'subPages._id': req.body.ID
}, {
  $pull: { subPages: { _id: req.body.ID } }
}, function (error, result) {
    console.log(result);
});

如果要删除所有子文档（即使subPages为空），可以$set 将其值设置为空数组。

Page.update({
  'subPages._id': req.body.ID
}, {
  $set: { subPages: [] }
}, function (error, result) {
    console.log(result);
});

希望能帮助到你。