I programming in react, mongodb, nodejs and expressjs. I have a problem that I cannot solve. I would like to use dynamic fields from $not on the server. For example, the server gets the column name from the front and it is supposed to return the number of documents where the text is different from an empty string, i.e. ''. I've tried to do something like this(code below), but it doesn't help.
const query = {};
query[type] = { $not: '' };
User.countDocuments(query, (err, data) => {
if (err) return res.json({ success: false, error: err });
return res.json({ success: true, data: data });
});
You are close, you probably were looking for $ne instead of $not. So changing it to
const query = {};
query[type] = { $ne: '' };
should fix the issue. This would find all documents where the dynamic type field does not equal ''. If you want to do the inverse, i.e. find all documents where the dynamic field equals an empty string, change it to:
query[type] = { $eq: '' };
Related
Here's the user schema and the part I want to update is ToDo under User.js (further down). I am attempting to add new data to an array within the db.
data.js
app.post("/data", loggedIn, async (req, res) => {
console.log(req.body.content);
let content = { content: req.body.content };
User.update({ _id: req.user._id }, { $set: req.body }, function (err, user) {
if (err) console.log(err);
if (!content) {
req.flash("error", "One or more fields are empty");
return res.redirect("/");
}
user.ToDo.push(content);
res.redirect("/main");
});
});
User.js
new mongoose.Schema({
email: String,
passwordHash: String,
ToDo: {
type: [],
},
date: {
type: Date,
default: Date.now,
},
})
Originally I was trying the .push() attribute, but I get the error:
user.ToDo.push(content);
^
TypeError: Cannot read property 'push' of undefined
First of all, your problem is the callback is not the user. When you use update the callback is something like this:
{ n: 1, nModified: 1, ok: 1 }
This is why the error is thrown.
Also I recommend specify the array value, something like this:
ToDo: {
type: [String],
}
The second recommendation is to do all you can into mongo query. If you can use a query to push the object, do this instead of store the object into memory, push using JS function and save again the object into DB.
Of course you can do that, but I think is worse.
Now, knowing this, if you only want to add a value into an array, try this query:
var update = await model.updateOne({
"email": "email"
},
{
"$push": {
"ToDo": "new value"
}
})
Check the example here
You are using $set to your object, so you are creating a new object with new values.
Check here how $set works.
If fields no exists, will be added, otherwise are updated. If you only want to add an element into an array from a specified field, you should $push into the field.
Following your code, maybe you wanted to do something similar to this:
model.findOne({ "email": "email" }, async function (err, user) {
//Here, user is the object user
user.ToDo.push("value")
user.save()
})
As I said before, that works, but is better do in a query.
I have a document in my mongoDB
I pass the object from my frontend (user should type something in input filed, for example he types 'test':
{'countdown': 'test'}
And then I pass it to my backend and want to check if he typed right
app.post('/answ', function(req, res) {
var query = req.body;
Model.find(query
, function(err, result) {
if (err) throw err;
if (result) {
if(result.length!== 0) {
res.json('ok');
} else {
res.json('not found');
}
} else {
res.send(JSON.stringify({
error : 'Error'
}))
}
})
});
So, if key-value pair exist, backend will return ok, otherwise not found.
It works for such simple object, but if I try to pass something like:
{'apilisttask': { 'port': '1', 'host': '2', 'path': '3', 'query': '4' } }
In this example user has 4 input fields, I gather all answers and pass it to the backend, but it doesn't give me ok even if the answers are right.
Could you please advice maybe a better approach to compare the data or how to fix the second comparison?
Since you are trying to find in an embedded document, you can not query embedded doc like that.
To query embedded doc, you need to do something like this:
Model.find({'apilisttask.port':query.apilisttask.port, 'apilisttask.host':query.apilisttask.host, ...}, function(err, result){
// ---
});
This should do the trick.
I am working on a MEAN stack application in which i defined a model using following schema:
var mappingSchema = new mongoose.Schema({
MainName: String,
Addr: String,
Mapping1: [Schema1],
Mappings2: [Schema2]
},
{collection : 'Mappings'}
);
I am displaying all this data on UI and Mapping1 & Mapping2 are displayed in the 2 tables where I can edit the values. What I am trying to do is once I update the values in table I should update them in database. I wrote put() api where I am getting these two updated mappings in the form of object but not able to update it in database. I tried using findAndModify() & findOneAndUpdate() but failed.
Here are the Schema1 & Schema2:
const Schema1 = new mongoose.Schema({
Name: String,
Variable: String
});
const Schema2 = new mongoose.Schema({
SName: String,
Provider: String
});
and my put api:
.put(function(req, res){
var query = {MainName: req.params.mainname};
var mapp = {Mapping1: req.params.mapping1, Mapping2: req.params.mapping2};
Mappings.findOneAndUpdate(
query,
{$set:mapp},
{},
function(err, object) {
if (err){
console.warn(err.message); // returns error if no matching object found
}else{
console.log(object);
}
});
});
Please suggest the best to way update those two arrays.
UPDATE :
I tried this
var mapp = {'Mapping2': req.params.mapping2};
Mappings.update( query ,
mapp ,
{ },
function (err, object) {
if (err || !object) {
console.log(err);
res.json({
status: 400,
message: "Unable to update" + err
});
} else {
return res.json(object);
}
});
what I got is
My array with size 3 is saved as String in Mapping2 array.
Please help. Stuck badly. :(
From Mongoose's documentation I believe there's no need to use $set. Just pass an object with the properties to update :
Mappings.findOneAndUpdate(
query,
mapp, // Object containing the keys to update
function(err, object) {...}
);
I am trying to fetch single value from my level collection using this level schema
After new Schema I use ( [] ) I don't know exactly the use of this. Why we use this. But my project requirement is to use this []
var LevelSchema = new Schema(
[
{
_id: { type: String },
age: { type: Number },
level_num: { type: Number },
min_score: { type: Number },
max_questions: { type: Number }
}
]);
So when I am trying to fetch the value using this node js
this.levelChange = function(req, res, next){
try{
var query = {level_num:1};
QuizLevels.find(query,function(err,data){
if(err){
return next(err);
}else if(data.min_score===10){
console.log(data.min_score);
}else{
console.log("Error");
}
});
}catch(err){
console.log(err);
}
};
I proper send all level information stored in my MongoDB to the browser. But when I am trying to fetch a single value field
min_score from the database and trying to send it in the browser or in the console it shows undefined. Means value cannot parse properly from MongoDB
to browser or console using this node js code.
so there are any further steps before to fetch this array schema.So that single value field parses properly to console
3). This is my JSON data
I am not sure that json data is exact according to level schema that i used to fetch.
{
"age":5,
"level_num":1,
"min_score":10,
"max_questions":30
}
{
"age":5,
"level_num":2,
"min_score":12,
"max_questions":33
}
I have a NodeJS application with Mongoose ODM(Mongoose 3.3.1). I want to retrieve all fields except 1 from my collection.For Example: I have a collection Product Which have 6 fields,I want to select all except a field "Image" . I used "exclude" method, but got error..
This was my code.
var Query = models.Product.find();
Query.exclude('title Image');
if (req.params.id) {
Query.where('_id', req.params.id);
}
Query.exec(function (err, product) {
if (!err) {
return res.send({ 'statusCode': 200, 'statusText': 'OK', 'data': product });
} else {
return res.send(500);
}
});
But this returns error
Express
500 TypeError: Object #<Query> has no method 'exclude'.........
Also I tried, var Query = models.Product.find().exclude('title','Image'); and var Query = models.Product.find({}).exclude('title','Image'); But getting the same error. How to exclude one/(two) particular fields from a collection in Mongoose.
Use query.select for field selection in the current (3.x) Mongoose builds.
Prefix a field name you want to exclude with a -; so in your case:
Query.select('-Image');
Quick aside: in JavaScript, variables starting with a capital letter should be reserved for constructor functions. So consider renaming Query as query in your code.
I don't know where you read about that .exclude function, because I can't find it in any documentation.
But you can exclude fields by using the second parameter of the find method.
Here is an example from the official documentation:
db.inventory.find( { type: 'food' }, { type:0 } )
This operation returns all documents where the value of the type field is food, but does not include the type field in the output.
Model.findOne({ _id: Your Id}, { password: 0, name: 0 }, function(err, user){
// put your code
});
this code worked in my project. Thanks!! have a nice day.
You could do this
const products = await Product.find().select(['-image'])
I am use this with async await
async (req, res) => {
try {
await User.findById(req.user,'name email',(err, user) => {
if(err || !user){
return res.status(404)
} else {
return res.status(200).json({
user,
});
}
});
} catch (error) {
console.log(error);
}
In the updated version of Mongoose you can use it in this way as below to get selected fields.
user.findById({_id: req.body.id}, 'username phno address').then(response => {
res.status(200).json({
result: true,
details: response
});
}).catch(err => {
res.status(500).json({ result: false });
});
I'm working on a feature. I store a userId array name "collectedUser" than who is collected the project. And I just want to return a field "isCollected" instead of "collectedUsers". So select is not what I want. But I got this solution.
This is after I get projects from database, I add "isCollected".
for (const item of projects) {
item.set("isCollected", item.collectedUsers.includes(userId), {
strict: false,
})
}
And this is in Decorator #Schema
#Schema({
timestamps: true,
toObject: {
virtuals: true,
versionKey: false,
transform: (doc, ret, options): Partial<Project> => {
return {
...ret,
projectManagers: undefined,
projectMembers: undefined,
collectedUsers: undefined
}
}
}
})
Finally in my controller
projects = projects.map(i => i.toObject())
It's a strange tricks that set undefined, but it really work.
Btw I'm using nestjs.
You can do it like this
const products = await Product.find().select({
"image": 0
});
For anyone looking for a way to always omit a field - more like a global option rather than doing so in the query e.g. a password field, using a getter that returns undefined also works
{
password: {
type: String,
required: true,
get: () => undefined,
},
}
NB: Getters must be enabled with option { toObject: { getters:true } }
you can exclude the field from the schema definition
by adding the attribute
excludedField : {
...
select: false,
...
}
whenever you want to add it to your result,
add this to your find()
find().select('+excludedFiled')