[英]How to find a sub-document using Mongoose?
我正在嘗試使用貓鼬在User
集合中獲取子文檔。 我在其官方網站上關注了貓鼬子文檔 。 上面寫着:
每個文檔都有一個_id。 DocumentArrays具有一種特殊的id方法,用於通過其_id查找文檔。
var doc = parent.children.id(id);
這是我的代碼:
exports.editAccount = function(req, res) {
var user = new User(req.user);
var newAccount = new Account(req.body);
console.log("Account:" + newAccount._id); // Gave me 53bf93d518254f880c000009
var account = user.accounts.id(newAccount._id);
console.log("Account" + account); // Never been printed
};
console.log("Account" + account);
從未被打印過。 我不知道會發生什么 我嘗試了許多不同的方法,但是仍然無法弄清楚。 任何幫助,將不勝感激。
用戶集合:
{
"__v" : 1,
"_id" : ObjectId("53bcf3e6fbf5adf10c000001"),
"accounts" : [
{
"accountId" : "123456789",
"type" : "Saving account",
"balance" : 100,
"_id" : ObjectId("53bf93d518254f880c000009")
}
]
}
一世
不太確定如何定義Schema或基本上甚至是模型實例,但是實際上所需要做的就是:
var accountSchema = new Schema({
"accountId": String,
"type": { "type": String, "enum": ["Saving Account", "Checking Account"] },
"balance": { "type": Number, "default": 0 }
]);
var userSchema = new Schema({
"accounts": [accountSchema]
]);
var User = mongoose.model( "User", userSchema );
然后,當您要將帳戶添加到您剛做的用戶時,假設您輸入的內容與第一個變量聲明相匹配:
var input = {
"accountId": "123456789",
"type": "Savings Account",
};
User.findByIdAndUpdate(
userId,
{ "$push": { "accounts": input } },
function(err,user) {
// work with result in here
}
);
這確實繞過了諸如驗證和其他掛鈎之類的事情,但是與MongoDB的通信效率更高。
如果您確實需要驗證和/或其他功能,則可以使用.find()
變體並發出.save()
方法。
User.findById(userId,function(err,user) {
if (err) throw err; // or handle better
user.accounts.push( input );
user.save(function(err, user) {
// more handling
});
]);
而要修改文檔,您將執行相同的操作。 通過最有效的MongoDB方法:
var input = {
accountId: "123456789",
amount: 100
};
User.findOneAndUpdate(
{ "_id": userId, "accounts.accountId": input.accountId },
{ "$inc": { "accounts.$.balance": input.amount } },
function(err,user) {
// handle result
}
);
或者再次需要Mongoose鈎子和/或驗證才能應用:
User.findById(userId,function(err,user) {
if (err) throw err; // or handle otherwise
user.accounts.forEach(function(account) {
if ( account.accountId === input.accountId )
account.balance += input.balance;
});
user.save(function(err,user) {
// handle things
});
);
請記住,這些都是“數組”,您可以用MongoDB方式或JavaScript方式處理它們。 這僅取決於您選擇在何處“驗證”您的輸入。
更多代碼說明用法不正確的地方:
var async = require('async'),
mongoose = require('mongoose'),
Schema = mongoose.Schema;
mongoose.connect('mongodb://localhost/child');
var accountSchema = new Schema({
"accountId": String,
"type": { "type": String },
"balance": { "type": Number, "default": 0 }
});
var userSchema = new Schema({
"accounts": [accountSchema]
});
var User = mongoose.model( "User", userSchema );
async.waterfall([
function(callback) {
User.create({},function(err,user) {
if (err) throw err;
console.log(
"Created:\n%s\n",
JSON.stringify( user, undefined, 4 )
);
callback(null,user);
});
},
function(user,callback) {
var account = user.accounts.create({
"accountId": "123456789",
"type": "Savings"
});
console.log(
"Account is:\n%s\n",
JSON.stringify( account, undefined, 4 )
);
console.log(
"User is still:\n%s\n",
JSON.stringify( user, undefined, 4 )
);
user.accounts.push( account );
console.log(
"User Changed:\n%s\n",
JSON.stringify( user, undefined, 4 )
);
User.findById(user.id,function(err,saved) {
if (err) throw err;
console.log(
"Persisted is still:\n%s\n",
saved
);
user.save(function(err,user) {
if (err) throw err;
callback(null,user,account);
});
});
},
function(user,account,callback) {
User.findById(user.id,function(err,saved) {
if (err) throw err;
console.log(
"Persisted is now:\n%s\n",
saved
);
var item = user.accounts.id(account.id);
console.log(
"Item is:\n%s\n",
item
);
callback();
});
}
],function(err) {
process.exit();
});
結果:
Created:
{
"__v": 0,
"_id": "53c08ab51083d1fe3852becc",
"accounts": []
}
Account is:
{
"accountId": "123456789",
"type": "Savings",
"_id": "53c08ab51083d1fe3852becd",
"balance": 0
}
User is still:
{
"__v": 0,
"_id": "53c08ab51083d1fe3852becc",
"accounts": []
}
User Changed:
{
"__v": 0,
"_id": "53c08ab51083d1fe3852becc",
"accounts": [
{
"accountId": "123456789",
"type": "Savings",
"_id": "53c08ab51083d1fe3852becd",
"balance": 0
}
]
}
Persisted is still:
{ _id: 53c08ab51083d1fe3852becc, __v: 0, accounts: [] }
Persisted is now:
{ _id: 53c08ab51083d1fe3852becc,
__v: 1,
accounts:
[ { accountId: '123456789',
type: 'Savings',
_id: 53c08ab51083d1fe3852becd,
balance: 0 } ] }
Item is:
{ accountId: '123456789',
type: 'Savings',
_id: 53c08ab51083d1fe3852becd,
balance: 0 }
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