重塑集合中的所有文档

本文介绍了重塑集合中的所有文档的处理方法，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

我的文档中具有以下结构:

I have the following structure in my documents:

{ "_id" : 1, "item" : { "name" : "abc", "price" : 10, "quantity" : 2, "date" : ISODate("2014-03-01T08:00:00Z") } }

我想在此上转换每个文档:

And I want to transform each document on this:

{ "_id" : 1, "name" : "abc", "price" : 10, "quantity" : 2, "date" : ISODate("2014-03-01T08:00:00Z") }

换句话说，删除嵌入的文档，但不删除细节！

In other words remove the embedded document but not the details!

谢谢！

推荐答案

您可以使用 aggregation ，尤其是 $project 运算符. $out 运算符可让您编写结果在另一个集合中.

You can use the aggregation especially the $projectoperator for that. The $out operator let you write the result in another collection.

db.collection.aggregate([ { "$project": { "_id": "$_id", "name": "$item.name", "price": "$item.price", "quantity": "$item.quantity", "date": "$item.date"} }, { "$out": "collection"} ])

您的文档现在看起来像这样:

You documents now look like this:

{ "_id" : 1, "name" : "abc", "price" : 10, "quantity" : 2, "date" : ISODate("2014-03-01T08:00:00Z") }

您还可以通过给新结果集合使用相同的名称来覆盖现有的集合.

You can also overwrite the pre-existing collection by giving the new results collection the same name but this.