node.js 如何在 Mongoose 中将 _id 设置为 db 文档？
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How to set _id to db document in Mongoose?
提问by EmptyArsenal
I'm trying to dynamically create _id's for my Mongoose models by counting the documents in the db, and using that number to create the _id (assuming the first _id is 0). However, I can't get the _id to set from my values. Here's my code:
我正在尝试通过计算数据库中的文档并使用该数字来创建 _id（假设第一个 _id 为 0）来为我的 Mongoose 模型动态创建 _id。但是，我无法从我的值中设置 _id。这是我的代码：
//Schemas
var Post = new mongoose.Schema({
//_id: Number,
title: String,
content: String,
tags: [ String ]
});
var count = 16;
//Models
var PostModel = mongoose.model( 'Post', Post );
app.post( '/', function( request, response ) {
var post = new PostModel({
_id: count,
title: request.body.title,
content: request.body.content,
tags: request.body.tags
});
post.save( function( err ) {
if( !err ) {
return console.log( 'Post saved');
} else {
console.log( err );
}
});
count++;
return response.send(post);
});
I've tried to set the _id a number of different ways, but it's not working for me. Here's the latest error:
我尝试以多种不同的方式设置 _id，但它对我不起作用。这是最新的错误：
{ message: 'Cast to ObjectId failed for value "16" at path "_id"',
name: 'CastError',
type: 'ObjectId',
value: 16,
path: '_id' }
If you know what's going on, please let me know.
如果你知道发生了什么，请告诉我。
回答by robertklep
You either need to declare the _idproperty as part of your schema (you commented it out), or use the _idoption and set it to false(you're using the idoption, which creates a virtual getter to cast _idto a string but still created an _idObjectID property, hence the casting error you get).
您要么需要将该_id属性声明为架构的一部分（您已将其注释掉），要么使用该_id选项并将其设置为false（您正在使用该id选项，该选项创建了一个虚拟 getter 来_id转换为字符串，但仍创建了一个_idObjectID属性，因此会出现铸造错误）。
So either this:
所以要么这样：
var Post = new mongoose.Schema({
_id: Number,
title: String,
content: String,
tags: [ String ]
});
Or this:
或这个：
var Post = new mongoose.Schema({
title: String,
content: String,
tags: [ String ]
}, { _id: false });
回答by timqian
The first piece of @robertklep's code doesn't work for me (mongoose 4), also need to disabled _id
@robertklep 的第一段代码对我不起作用（mongoose 4），也需要禁用 _id
var Post = new mongoose.Schema({
_id: Number,
title: String,
content: String,
tags: [ String ]
}, { _id: false });
and this works for me
这对我有用
回答by jenish
Create custom _id in mongoose and save that id as a mongo _id. Use mongo _id before saving documents like this.
在 mongoose 中创建自定义 _id 并将该 id 保存为 mongo _id。在保存这样的文档之前使用 mongo _id 。
const mongoose = require('mongoose');
const Post = new mongoose.Schema({
title: String,
content: String,
tags: [ String ]
}, { _id: false });
// request body to save
let post = new PostModel({
_id: new mongoose.Types.ObjectId().toHexString(), //5cd5308e695db945d3cc81a9
title: request.body.title,
content: request.body.content,
tags: request.body.tags
});
post.save();
