Hi im trying to simply remove a document from a collection using mongoose but for some strange reason I cannot get it to work.
Here is the code:
function deleteUserevent()
{console.log('in delete User Event');
models.Userevent.remove({ _id: "5214f4050acb53fe31000004"}, function(err) {
if (!err){
console.log('deleted user event!');
}
else {
console.log('error');
}
});
}
Can anyone help me out on my syntax? I know the _id is stored as new ObjectId("5214f4050acb53fe31000004") but I have tried this with no joy?
Thanks.
In MongoDB, the "_id" field of documents is of type ObjectId, as you mentioned. This is not equal to a String, so running the query
db.userevent.remove({ _id: "5214f4050acb53fe31000004"});
will not match anything, and will not remove anything. Instead, you must search for a document where the _id field is an ObjectId with that value:
db.userevents.remove({ _id: ObjectId("5214f4050acb53fe31000004")});
In mongoose, you can use the findByIdAndRemove command to remove a document with a specific _id. This command takes either an ObjectId or a String as an argument, so
query = Userevent.findByIdAndRemove("5214f4050acb53fe31000004");
should work just fine.
Just add exec() after query.
It should work like this:
await models.Userevent.findByIdAndDelete("5214f4050acb53fe31000004").exec()
Related
I wish to return just the document id's from mongo that match a find() query.
I know I can pass an object to exclude or include in the result set, however I cannot find a way to just return the _id field.
My thought process is returning just this bit of information is going to be way more efficient (my use case requires no other document data just the ObjectId).
An example query that I expected to work was:
collection.find({}, { _id: 1 }).toArray(function(err, docs) {
...
}
However this returns the entire document and not just the _id field.
You just need to use a projection to find what ya want.
collection.find({filter criteria here}, {foo: 0, bar: 0, _id: 1});
Since I don't know what your document collection looks like this is all I can do for you. foo: 0 for example is exclude this property.
I found that using the cursor object directly I can specify the required projection. The mongodb package on npm when calling toArray() is returning the entire document regardless of the projection specified in the initial find(). Fixed working example below that satisfies my requirements of just getting the _id field.
Example document:
{
_id: new ObjectId(...),
test1: "hello",
test2: "world!"
}
Working Projection
var cursor = collection.find({});
cursor.project({
test1: 0,
test2: 0
});
cursor.toArray(function(err, docs) {
// Importantly the docs objects here only
// have the field _id
});
Because _id is by definition unique, you can use distinct to get an array of the _id values of all documents as:
collection.distinct('_id', function(err, ids) {
...
}
you can do like this
collection.find({},'_id').toArray(function(err, docs) {
...
}
Why dosen't db.find work? The console.log gets undefined...
var course = (db.courses.find({ _id: mongo.helper.toObjectID(param.course)}));
console.log(course.body)
The way you are trying use Selects documents in a collection and returns a cursor to the selected documents., so you can't use the way you are trying to use it.
You need to use a callback() to get the records matching the query.
The below code will give result in an array format :-
db.courses.findOne({ _id: mongo.helper.toObjectID(param.course)}).toArray(function(err, result)
{
console.log(result[0]); // will give you the matched record.
})
I am working on a query that need to update a subdocument in meteor mongo. My code looks like this:
Cases.update(
{"_id":doc._id,"notes._id": doc.noteid},
{$set:{
'notes.$': {
'note': doc.note,
'updatedBy': currentUser,
'updatedAt': date
}
}});
this does work, however it does remove other fields that are not in the update such as "createdAt" and "date". I went as far as doing this but i get the same result:
Cases.update(
{"_id":doc._id,"notes._id": doc.noteid},
{$set:{
'notes.$': {
'note': doc.note,
'updatedBy': currentUser,
'updatedAt': date,
'createdBy':doc.createdBy,
'date': doc.date,
'_id':doc.noteid
}
}});
the notes.$._id, date and createdBy fields are removed in the opertion. I am using aldeed simple schema and collection 2 as packages of the autoForm package. This update is however been done using a generic form with a Meteor.call. I am using meteor 1.2.1. I know that collection 2 has the removeEmptyString setting turned on by default that is why I tried doing it the second way but it still does not work. Can some one please help?
Your $set is saying, "Assign the notes.$ object to this object I'm giving you, and delete whatever is currently there."
You want to do something like:
Cases.update( {"_id":doc._id, "notes._id": doc.noteid},
{
$set:{
'notes.$.note': doc.note,
'notes.$.updatedBy': currentUser,
'notes.$.updatedAt': date
}
});
My $set is saying, "Assign these three particular fields of the notes.$ object to the values I'm giving you, and don't touch anything else."
Why does this query not work in Mongoskin? (where itemID is a Mongo ObjectID)
{"_id": itemID}
I know that there is truly an element that has a matching _id because if I run this same query through the MongoDB shell it works. Why doesn't it work with Mongoskin?
var ObjectId = require('mongodb').ObjectID;
Notice: the name of the factory function is ObjectID, instead of ObjectId
Then you can use:
db.collection('XXX').update({_id: ObjectId(XXX)}, {$set: {XXX : XXX}});
Well, db is a wrapped function of mongoskin:
module.exports = (function() {
return require('mongoskin').db('mongodb://localhost:27017/db_name');
})();
It turns out that mongoskin uses a different type of ObjectID than vanilla mongoDB. I was using another library to convert my string to an ObjectID, hence the confusion. Here's what worked for me to get the proper ObjectID object:
require('mongoskin').ObjectID.createFromHexString(hexString);
For this app, I'm using Node.js, MongoDB, Mongoose & Express
So I have a Param Object that contains an array of Pivots, and I want to read certain data from the pivots as outlined below
---in models.js-------------------------
var Pivot = new Schema({
value : String
, destination : String
, counter : Number
});
var Param = new Schema({
title : String
, desc : String
, pivots : [Pivot]
});
------------- in main.js --------------
var Param = db.model('Param');
app.get('/:title/:value', function(req, res){
Param.findOne({"title":req.param('title')}, function(err, record){
console.log(record.pivots);
record.pivots.find({"value":req.param('value')}, function(err, m_pivot){
pivot.counter++;
res.redirect(m_pivot.destination);
});
record.save();
});
});
I know that the code works until console.log(record.pivots), since i got a doc collection with the right pivot documents inside.
However, there does not seem to be a find method to let me match an embedded document by the 'value' property defined in the schema. Is it possible to search through this array of embedded documents using .find() or .findOne() , and if not, is there some easy way to access it through mongoose?
varunsrin,
This should do it
app.get('/:title/:value', function(req, res) {
Param.findOne({'pivots.value': req.param('value'), "title":req.param('title')}},
function(err, record) {
record.pivot.counter++;
res.redirect(m_pivot.destination);
record.save();
});
});
Note the pluralization of the query to match the field name in your schema
You can querying using embedded document properties like this:
{'pivot.value': req.param('value')}}
Update in response to comment:
app.get('/:title/:value', function(req, res) {
Param.findOne({'pivot.value': req.param('value'), "title":req.param('title')}},
function(err, record) {
record.pivot.counter++;
res.redirect(m_pivot.destination);
record.save();
});
});
I solved it temporarily using a simple for loop to parse the object array as follows:
for (var i=0; i <record.pivots.length; i++){
if (record.pivots[i].value == req.param('value')){
res.redirect(record.pivots.destination);
}
}
However, I still think that Mongoose must have a simpler way of interacting with embedded documents - and this loop is somewhat slow, especially when the number of embedded documents grows large.
If anyone has any suggestions for a faster way to search this object array either in js or with a mongoose function, please post below.
the biggest problem with this is that if your req has some fields empty (that should act as wildcard), you will not find anything since mongo tries to match empty params as well, so searching for {"user":"bob", "color":""} is not the same as {"user":"bob", "color":"red"} or {"user":"bob"}. this means that you have to first create a query object and filter out any unused parameters before you pass it in, and if you create a query object, you can no longer do something like "user.name=..." because mongo interperets this as an error since it does not first resolve the object literal into a string.
Any ideas on this problem?
ps. You'd think it would be easy enough to make an object like:
user.name="bob"; user.color:"green"; user.signup.time="12342561"
and then just use user as a query object :/
I think you are looking for the "$in" keyword?
As in:
{a: {$in: [10, "hello"]}}
source: MongoDB Queries CheatSheet