在 mongoDB (mongoose) 中按虚拟字段排序 [英] Sorting by virtual field in mongoDB (mongoose)

问题描述

假设我有一些 Schema，它有一个像这样的虚拟字段

Let's say I have some Schema which has a virtual field like this

var schema = new mongoose.Schema(
{
    name: { type: String }
},
{
    toObject: { virtuals: true },
    toJSON: { virtuals: true }
});

schema.virtual("name_length").get(function(){
    return this.name.length;
});

在查询中是否可以按虚拟字段对结果进行排序?类似的东西

In a query is it possible to sort the results by the virtual field? Something like

schema.find().sort("name_length").limit(5).exec(function(docs){ ... });

当我尝试这个时，结果很简单，没有排序...

When I try this, the results are simple not sorted...

推荐答案

您将无法按虚拟字段排序，因为它们未存储到数据库中.

You won't be able to sort by a virtual field because they are not stored to the database.

虚拟属性是方便携带的属性但这不会持久化到 mongodb.

Virtual attributes are attributes that are convenient to have around but that do not get persisted to mongodb.

http://mongoosejs.com/docs/2.7.x/docs/virtuals.html

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