猫鼬:在保存时根据父字段值设置子文档字段值

本文介绍了猫鼬:在保存时根据父字段值设置子文档字段值的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

几乎可以肯定在其他地方有介绍，但是:

This is almost certainly covered elsewhere, but:

如果我有一个带有嵌入式子文档的架构，例如:

If I have a single schema with an embedded sub-document, like so:

var ChildSchema = new Schema ({ name : { type: String, trim: true }, user :{ type: String, trim: true } }) var ParentSchema = new Schema ({ name : { type: String, trim: true }, child : [ChildSchema] })

如何在同一.save()操作中将ParentSchema的名称保存为ParentSchema.name和ChildSchema.name?以下内容根本不起作用.

How would I save the name of the ParentSchema to ParentSchema.name and to ChildSchema.name in the same .save() action? The following does not work at all.

ChildSchema.pre('save', function(next){ this.name = ParentSchema.name; next(); });

推荐答案

您可以通过将中间件移动到ParentSchema来进行访问，该中间件可以访问其自身及其子级:

You can do that by moving the middleware to ParentSchema which has access to itself and its children:

ParentSchema.pre('save', function(next){ var parent = this; this.child.forEach(function(child) { child.name = parent.name; }); next(); });