So I have an update one function going i just need to know how to update one of the elements in an array rather than wipe and replace the whole thing.
labelRelease = function(db, callback){
db.collection($$showName).updateOne(
{'showName' : $$showName},
{
$set: {'episode[2]' : data + label}
}, function(err, results){
callback();
});
}
Is a stripped down version of the code I am using to update, obviously the episode[2] does not work to select only one array element how can i achieve this?
relevant part of the database
episode:[episode1, episode2, episode3.....]
You can update an array element by position by using dot notation:
labelRelease = function(db, callback){
db.collection($$showName).updateOne(
{'showName' : $$showName},
{
$set: {'episode.2' : data + label}
},
function(err, results){
callback();
});
};
If the index of 2 is in a variable, you need to build up your $set value in a couple steps:
var index = 2;
var setValue = {};
setValue['episode.' + index] = data + label;
labelRelease = function(db, callback){
db.collection($$showName).updateOne(
{'showName' : $$showName},
{
$set: setValue
},
function(err, results){
callback();
});
};
The correct syntax for the set operation is:
$set: { 'episode.2' : ... } }
Note that episode.2 refers to the 3rd element of the episode array.
Related
I am using Node and Mongoose, and trying to set an array of ISODate elements:
"visitLog" : [
ISODate("2017-10-22T22:43:49.571Z"),
ISODate("2017-10-22T22:44:39.572Z"),
ISODate("2017-10-22T23:35:36.111Z"),
ISODate("2017-10-22T23:48:26.516Z"),
ISODate("2017-10-22T23:50:33.378Z"),
ISODate("2017-10-22T23:53:56.227Z"),
ISODate("2017-10-22T23:57:20.986Z")
]
So I had an existing schema where visitLog field did not existed, added new field to a schema - visitLog: [ {type: Date, default: '' }],and it worked - the result is what you see above.
But when I created a new document with updated schema that already has an empty array in it - "visitLog" : [ ] , $push just stopped working.
Here is mongoose query, if needed:
// conditions is a ternary operator that checks whether req.body username
// is an email or not, and puts needed condition to a query
var conditions = (!/^[a-zA-Z0-9\-\_\.\+]+#[a-zA-Z0-9\-\_\.]+\.[a-zA-Z0-9\-\_]+$/.test(req.body.username)) ? ' {email: req.body.username } ' : ' {username: req.body.username } ';
var fieldsToSet = {
$push: {
visitLog: new Date().toISOString(),
}
};
var options = { upsert: true };
User.findOneAndUpdate(conditions, fieldsToSet, options, function(err, user) { ...
The working document was created in mongo console, while the second was generated on a server, but I can't how can this make any difference.
Using $push shuld work with empty arrays. Can someone explain what's wrong here?
Thank you.
Edit
It figures that using findByIdAndUpdate without conditions works for both documents:
var fieldsToSet = {
$push: {
visitLog: new Date().toISOString(),
}
};
var options = { new: true };
req.app.db.models.User
.findByIdAndUpdate(req.user.id, fieldsToSet, options, function(err, user) {
You can do with the following query.
User.findOne(condiitons, (err, user) => {
if (user) {
var date = new Date().toISOString();
user.visitLog.push(date);
user.save();
...
}
});
I am using mongoose ODM and have a schema which looks like this:
var banSchema = new Schema({
userid: { type: String, required: true, unique: true },
name: String,
groupid: String,
reason: String,
timestamp: Date
});
I want to output every single user id from all documents in the collection. I am using this query to obtain the userid objects. However I cannot seem to get the full list automatically. I have to manually enter the object number as seeen below:
bot.onText(/\/sync/i, function (msg) {
var fromId = msg.from.id;
var chatId = msg.chat.id;
if (fromId == config.sudo) {
console.log('Sudo Confirmed And Authorized!');
Ban.find({}, function (err, obj) {
console.log(obj[0].userid); // Returns A Single ID
console.log(obj[1].toObject().userid); // Returns a different ID
bot.sendMessage(chatId, obj[1].toObject().useridid);
});
} else {
console.log('Someone Is Trying To Act Like Sudo! *sigh*');
bot.sendMessage(chatId, 'You Are Not A Mod!');
}
});
This however does not return a full list of id's as I want. How could I solve this issue?
The code above is for a telegram bot which on a /sync command it should return a message with all ids from the collection.
Telegram bot API Limits
Due to the API limits, the entire output should be in a single message.
var query = Ban.find({}).select({
"userid": 1,
//Add more column fields here
"_id": 0 //Ensures _id is not displayed
});
var arr = [];
query.exec(function (err, results) {
if (err) throw err;
results.forEach(function (result) {
arr.push(result.userid);
// Add more column fields here;
});
var fixedJoin =arr.join("\n");
console.log(fixed);
bot.sendMessage(chatId, 'List\n\n' + fixedJoin);
});
The easiest way to get all values of a particular field across all docs in the collection is to use distinct:
Ban.distinct('userid', function (err, userids) {
// userids is an array containing all userid values in the collection.
// string.join into a single string for the message.
bot.sendMessage(chatId, 'USER IDs\n\n' + userids.join('\n'));
});
Use this syntax
Ban.find({}).
select('userid').
exec(function(err, result) {
//result is array of userid of all document
});
You can use this syntax:
Ban.find({}, 'userid', function(err, users) {
users.forEach(function(user) {
console.log(user);
bot.sendMessage(chatId, 'users \n' + user);
});
})
I am creating a MEAN Stack application. My post function is as follows:
app.post('/updateGroup/:id', function(req, res) {
var id = req.params.id; // = mongoDB ObjectID ie: "55616e2a37e8728266ceac6"
var vals = {};
vals['hostName'] = req.body.hostName // = a String ie, "Steve"
// this is a different name value than the
// current hostName key that is in
// the groupList db
db.groupList.update(
{"_id": id},
{$set : vals},
function(err, result) {
if (err) {
console.log(err);
}
else {
console.log(result);
}
}
);
});
When I access this function in my front-end Angular code my
console.log(result);
Comes out as:
{ ok: true, n: 0, updatedExisting: true }
But I should see n: 1 to indicate there was an update? Why is my Node application not updating my mongoDB key:value pair?
Is there something about db.collection.update() that I'm missing?
I was able to figure it out:
When assigning the _id query I needed to do it like this:
id['_id'] = mongojs.ObjectId(req.params.id);
In my users profile collection I have array with image objects in it.
A user can have a max of 3 images in their profile collection. If the user has 3, throw an error that the maximum has been reached. The user has the option to remove an image themselves in the frontend.
I thought the solution would be to check the length of the array with $size. if it's less then 3, insert the image, else throw error.
I'm using the tomi:upload-jquery package.
client:
Template.uploadImage.helpers({
uploadUserData: function() {
return Meteor.user();
},
finishUpload: function() {
return {
finished: function(index, fileInfo, context) {
Meteor.call('insert.profileImage', fileInfo, function(error, userId) {
if (error) {
// todo: display modal with error
return console.log(error.reason);
} else {
// console.log('success ' +userId);
// console.log('success ' + fileInfo);
}
});
}
};
}
});
The method (server) I use:
'insert.profileImage': function(postImage) {
check(postImage, Object);
// check array profile.images max 3
Meteor.users.update(this.userId, {
$push: {
'profile.images': postImage
}
});
},
You may do it with a function using the $where operator:
'insert.profileImage': function(postImage) {
var updateResults;
check(postImage, Object);
updateResults = Meteor.users.update(
{
_id : this.userId,
$where : 'this.profile.images.length < 3' //'this' is the tested doc
},
{
$push: {
'profile.images': postImage
}
});
if(updateResults === 0) {
throw new Meteor.Error('too-many-profile-images',
'A user can only have up to 3 images on his/her profile');
}
},
The Mongo docs warns about potential performance issues (if you run a JavaScript function on all documents of the store, you're in for bad surprises) but since we also search by _id I guess it should be fine.
This way, the update just doesn't run if the user has too many images. You can also check the number of affected document (the return value of the update) to know if something happened. If nothing (returns 0) happened, there's not many possibilities: The user has too many images.
Use the $exists operator to check the existence of all documents that have at least a fourth profile image array element (index position 3) with the dot notation. For example you could use it to check whether the size of the profile.image array is greater than 3 with the find() method as follows:
var hasSizeGreaterThanThree = Meteor.users.find(
{
'_id': this.userId,
'profile.image.3': { '$exists': true }
}).count() > 0;
So you could use that in your code as:
'insert.profileImage': function(postImage) {
check(postImage, Object);
// check array profile.images max 3
var hasSizeGreaterThanThree = Meteor.users.find(
{
'_id': this.userId,
'profile.image.3': { '$exists': true }
}).count() > 0;
if (!hasSizeGreaterThanThree){
Meteor.users.update(this.userId, {
$push: {
'profile.images': postImage
}
});
}
},
My Schema is as below. A student can participate in any no. of events.and each Event can have any number of students.
Student{
name:String,
age:Number,
.
.
.,
events:{
type:
[
{type:Schema.ObjectId,
ref:'Event'}
]
}
}
Event{
title:String,
desc:String,
eventDate:Date,
participants:{
type:
[{
student: {type:Schema.ObjectId,
ref:'Student'},
status : String
}]
}
}
My requirement:
Every time,I create an event, I need to push all the participants of that event inside event object. and in turn, tag the event reference inside all the participants.
My code is
function handleTeamParticipants(eventObj, participants) {
Student
.find({
$or: [{
_id: participants[0].student._id
}, {
_id: participants[1].student._id
}]
})
.populate('events events.participants events.participants.student')
.exec(function(err, students) {
var studentLength = students.length,
result = [];
var saveAll = function() {
var doc = students.pop();
Student.populate(doc, {
path: 'events.participants.student',
model: 'Student'
}, function(err, student) {
student.events.push(eventObj);
student.save(function(err, saved) {
if (err) next(err); //handle error
result.push(saved);
if (--studentLength) saveAll();
else // all saved here
{
return res.status(200).send(eventObj);
}
});
});
};
saveAll();
});
}
This code is working.
So, this way, I get only the first two participants updated and in turn added to eventobj. But I want the find query to select all the participants.student._id
Please let me know the easy way to do it.
Thanks.
I used lodash method pluck.
lodash.pluck(< arrayObj >,< attribute >);
will give the list of attribute values in the arrayObj.
studentList = lodash.pluck(pariticipants,"student");
studentIdList = lodash.pluck(studentList,"_id");