猫鼬的预钩子：从数组中删除_id

Question

我有两个模式：

技能专长：

var mongoose = require("mongoose");

var SkillSchema = new mongoose.Schema({

    skill: { type: String },

    tally: { type: Number, default: 0 },

    associatedUsers: { type: Array },

});

module.exports = mongoose.model("Skills", SkillSchema);

轮廓：

var mongoose = require("mongoose");

var passportLocalMongoose = require("passport-local-mongoose");

var profileSchema = new mongoose.Schema({ 

    username: String,

    password: String,

    skills: { type: Array }

    }

);

profileSchema.plugin(passportLocalMongoose);

module.exports = mongoose.model("Profile", profileSchema);

该Skills文档包含与各种users（Skills. Skills.associatedUsers）相关的技能：

{

    "_id" : ObjectId("5cab5c8788368eafb68b75a4"),

    "skill" : "cooking",

    "__v" : 0,

    "associatedUsers" : [

        ObjectId("5cab5c7d88368eafb68b75a0"),

        ObjectId("5cab546a7fb2b3a71c0404fa")

    ],

    "tally" : 0

}

该Profile文档包含一系列技能：

{

    "_id" : ObjectId("5cab546a7fb2b3a71c0404fa"),

    "skills" : [

        "cooking", "cleaning"

    ],

    "__v" : 0,

    "username" : "deleteMe"

}

我正在尝试在Profile架构中实现预挂钩，以便在删除用户时，也删除user._idin的任何实例Skills.associatedUsers。

我尝试了以下操作，但实际上删除了该技能的整个条目：

const Skills = require("./skills");

profileSchema.pre('remove', async function(){

    console.log("clearing user ID from skills model");

    await Skills.remove({associatedUsers: { $in: this._id } });

});

module.exports = mongoose.model("Profile", profileSchema);

我怎样才能pull在._id从待删除的用户associatedUsers的数组Skills文件？

Answer 1

您需要update使用$ pull运算符，并指定multi: true从profile集合中的所有文档中删除该值：profileSchema.pre('remove', async function(){    console.log("clearing user ID from skills model");    await Skills.update({}, { $pull: { associatedUsers: { $in: this._id } } }, { multi: true });});