本文介绍了在 mongodb 中更新子文档?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
我如何定位 authors
数组中的子文档,如下所示,以便更新它?
How do I target an subdocument in the authors
array as shown below, in order to update it?
collection.update({'_id': "4f44af6a024342300e000001"}, {$set: { 'authors.?' }} )
文档:
{
_id: "4f44af6a024342300e000001",
title: "A book",
created: "2012-02-22T14:12:51.305Z"
authors: [{"_id":"4f44af6a024342300e000002"}]
}
推荐答案
通过像这样指定嵌入文档的实际位置:
By specifying actual position of embedded document like this:
// update _id field of first author
collection.update({'_id': "4f44af6a024342300e000001"},
{$set: { 'authors.0._id': "1" }} )
或者通过位置运算符:
// update _id field of first matched by _id author
collection.update({'_id': "4f44af6a024342300e000001",
//you should specify query for embedded document
'authors._id' : "4f44af6a024342300e000002" },
// you can update only one nested document matched by query
{$set: { 'authors.$._id': "1" }} )
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