[英]MongoDB and NodeJS get related data from 3 collections
i have a mongoDB query to get data with $group and $count. 我有一个mongoDB查询来获取$ group和$ count的数据。 This data contains the _id from other documents collection. 此数据包含来自其他文档集合的_id。 How can i get the other documents by its _id in NodeJS and MongoDB asyncrohnous? 我如何通过NodeJS和MongoDB中的_id异步获取其他文档?
db.orders.aggregate([
{$match: { 'works.TechnicianId': {$in:['53465f9d519c94680327965d','5383577a994be8b9a9e3f01e']},
'works.Date': {$gte: ISODate("2013-05-21T06:40:20.299Z"), $lt: ISODate("2016-05-21T06:40:20.299Z")}}},
{$unwind: "$works" },
{$group: {_id: "$works.TechnicianId",total:{$sum:'$works.price'},ordersId: { $push: "$_id" }}},
])
This is the result: 结果如下:
{
"result" : [
{
"_id" : "53465f9d519c94680327965d",
"total" : 198,
"ordersId" : [
ObjectId("537b5ea4c61b1d1743f4341f"),
ObjectId("537b4633021d75bd36863f29")
]
},
{
"_id" : "5383577a994be8b9a9e3f01e",
"total" : 22,
"ordersId" : [
ObjectId("537b5ea4c61b1d1743f4341f"),
ObjectId("537b4633021d75bd36863f29")
]
}
],
"ok" : 1
}
Now i need to get from orders collection the documents with id from ordersId, and from other collection the documents with _id from the result _id field. 现在,我需要从订单集合中获取具有来自ordersId的id的文档,并从其他集合中获取来自结果_id字段的具有_id的文档。
I try with this: 我尝试这样:
var collection = db.collection('orders');
var result = [];
collection.aggregate([
{
$match: {
'works.TechnicianId': {
$in: ids
},
'works.Date': {
$gte: new Date(startDate),
$lt: new Date(endDate)
}
}
},
{
$unwind: "$works"
},
{
$group: {
_id: "$works.TechnicianId",
total: {
$sum: '$works.price'
},
orderId: {
$push: "$_id"
}
}
}
],
function (e, docs) {
if (e) {
error(e);
}
var usersCollection = db.collection('users');
_.each(docs, function (doc) {
usersCollection.findOne({_id: new ObjectID(doc._id)}, function (e, doc) {
doc.tech = doc;
});
doc.orders = [];
_.each(doc.orderId, function (queryOrder) {
collection.findOne({_id: new ObjectID(queryOrder._id)}, function (e, order) {
doc.orders.push(order);
});
});
success(docs);
});
});
But the success its called before all the _.eachs are finished..Any help, or idea? 但是成功要在所有_.each都完成之前调用。.有什么帮助或想法吗?
Edit: 编辑:
I try with Q promises, this is my code: 我尝试使用Q promises,这是我的代码:
var usersCollection = db.collection('users');
var promises = [];
_.each(reports, function (report) {
var promise = usersCollection.findOne({_id: new ObjectID(report._id)}).then(
function (e, orderUserReported) {
if (e) {
error(e);
}
report.tech = orderUserReported;
_.each(orderUserReported.orderId, function (queryOrder) {
collection.findOne({_id: new ObjectID(queryOrder._id)}, function (e, order) {
report.orders.push(order);
});
});
});
promises.push(promise);
});
Q.allSettled(promises).then(success(reports));
and the error: 和错误:
/Users/colymore/virteu/aa/server/node_modules/mongodb/lib/mongodb/connection/base.js:245
throw message;
^
TypeError: Cannot call method 'then' of undefined TypeError:无法调用未定义的方法“ then”
Because of asynchronous execution you have to wait until results are returned. 由于异步执行,您必须等到返回结果。 There are several options available: 有几种可用的选项:
Async is closer to your current code, you could use async.parallel https://github.com/caolan/async#parallel to wait untill you get data back 异步更接近您当前的代码,您可以使用async.parallel https://github.com/caolan/async#parallel来等待,直到您获得数据
Update 更新
Mongoose functions don't return Q promises, so you need to convert mongoose calls to promises by using something like Q.denodeify(User.findOne.bind(models.User))({ _id: userId}).then(...
猫鼬函数不会返回Q许诺,因此您需要使用Q.denodeify(User.findOne.bind(models.User))({ _id: userId}).then(...
For your case Q.denodeify(userCollection.findOne.bind(userCollection))({_id: new ObjectID(report._id)}).then(...
对于您的情况Q.denodeify(userCollection.findOne.bind(userCollection))({_id: new ObjectID(report._id)}).then(...
Short answer: Use promises. 简短的答案:使用承诺。 Look at Q.allSettled ( https://github.com/kriskowal/q ) Just run success asynchronously when all subtask are done. 查看Q.allSettled( https://github.com/kriskowal/q )当所有子任务都完成时,异步运行成功。
Also using https://github.com/iolo/mongoose-q package may be helpful to not combine mongoose promises with Q ones if you want use mongoose in your mongo. 如果您想在您的mongo中使用猫鼬,也可以使用https://github.com/iolo/mongoose-q软件包将不将猫鼬的承诺与Q的承诺相结合可能会有所帮助。
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