Im not able to fetch the field value i need only the value of the particular field in node js query, but coming undefined
I need the nodejs query of this mongodb query
Try using projection into find query to return only values you want.
Also don't forget to use await or get the field name into then. And, of course, the query should return any document to get the field.
Check this example which would be similar in Node:
const value = await db.collectionsname.findOne({mobilenumber: mobilenumber},{_id: 0, field: 1}).fieldname
Projection stage is not mandatory but if you only want that value is a good practice not get all document from the DB.
Related
I am trying to query an old mongoDB collection in node.js with the native driver.
It uses Legacy UUID as its _id field.
In my code I am using Binary values such as: "2u0kLwUZuEWQvjqOjgQU4g=="
and I want to query the collection with find() operation.
When trying to test it directly with mongoDB I am able to use the following query:
db.getCollection('myCollection').find({_id: BinData(3, "2u0kLwUZuEWQvjqOjgQU4g==")})
to find my item.
But what I need to do is to find multiple items.
So I need to use something like this:
db.getCollection('myCollection').find({_ids: { $in: [BinData(3, "2u0kLwUZuEWQvjqOjgQU4g=="), BinData(3, "3u0kLwUZuEWQvjqOjgQU4g==")...]}})
but it does not seem to work and always returns zero records.
I am not sure why? and what might be the correct way to query multiple Legacy UUIDs?
First time working with MongoDB. This query works for me in cmd line:
db.secrets.update({_id: ObjectId("5f767cd481cea1687b3dbf86")}, {$set: {secret_rating: 5}})
However, updating a record using essentially the same query on my node server is not completing this task when pinged. Am I wrong in trying to query for a record like so in my model? ObjectId obviously isn't native to my server.
db.secrets.update({_id: "5f767cd481cea1687b3dbf86"}, {$set: {secret_rating: 5}})
Assuming you're using the Nodejs Mongodb driver and not some ORM (since it hasn't been specified), two points of concern:
As far as my knowledge serves, if you have a connection object to your desired database in the db variable, you cannot reference collections directly such as you've done with db.secrets; you must instead use the collection method like so:
const secrets = db.collection("secrets");
secrets.find({
/*your query here*/
}).then((results) => {})
So, unless you've assigned db.secrets with db.collection("secrets") you should be getting an error, Cannot read property "update" of undefined. But I'm going to assume you've got the collection object in db.secrets since you did not mention you're getting that error.
You seem to be using a string instead of an ObjectID object. You can import the ObjectID constructor from the nodejs driver like so:
const ObjectID = require('mongodb').ObjectID
Then in your query, you will have to make a new ObjectID to get the correct result:
db.collection("secrets").find({
_id: new ObjectID("5f767cd481cea1687b3dbf86")
}).then((results) => {})
NOTE: The ObjectID constructor will throw an error if the string supplied to it is not a valid, 24-char hex string, so, if you're getting the id string as an input from somewhere (say, as a parameter in an API or as a command line argument), you might want to wrap it in a function that handles that error.
I come from MySQL world so mongo queries are a bit difficult to make considering I can't really make sense of mongo style queries. I am trying to make a query for finding a string. The problem is from my very primitive knowledge about mongodb queries, the query I made isn't working. I tried it in mongoose as well in mongo shell.
Schema:
mongoose.Schema({
doctorID : String,
patientIDList : Array // array of strings
});
Query Objective:
I want to find a doctor with doctorID and then look inside the patientIDList for an ID xxx. If the patientIDList doesn't contains xxx then add xxx in the list otherwise just add nothing.
Query:
The 2 queries I tried
MyModel.findOne({'doctorID':newAppointment.doctorID}, {'patientIDList' : newAppointment.patientID}, function(err){...});
MyModel.findOne({'doctorID': newAppointment.doctorID, 'patientIDList': newAppointment.patientID}, function(err){...});
What am I doing wrong? How can I make a query?
It's always a bit of challenge to switch from a SQL to NoSQL DB and other way around. What you are trying to do is check if a value exists in an array. If the array is a string array you can simply query for the value in array.
MyModel.findOne({doctorID : newAppointment.doctorID}, {patientIDList :newAppointment.doctorID}, function(err, res){
console.log(err, res);
})
Further read: https://docs.mongodb.com/manual/tutorial/query-documents/#match-an-array-element
Relevant Question: Find document with array that contains a specific value
I'm trying to do a 'findOne' operation in a model that has an array property and filter the results to only list the item if the string im searching is in that array.
Example:
var AppUser = server.loopback.getModel('AppUser');
AppUser.create({
"name":"juan"
"favoriteLetters":["a","b","c"]
},function(){
AppUser.findOne({where:{favoriteLetters:'a'}},function(error,appUser){
console.log(error,appUser);
});
});
So in this case i want to find a 'appUser' that has a favorite letter 'a'.
Thanks.
As far as I understood, possibility of such kind of a query depends on the underlying datasource and is not supported yet for relational DBs. But should be fine with memory storage or mongodb. More details and syntax for query is here: https://groups.google.com/d/msg/loopbackjs/8c8kw8EMiPU/yev3lsmrTFUJ
For anyone else who lands here, that query in your model is correct (for Mongo anyways).
{where:{favoriteLetters:'a'}
Reference:
Find document with array that contains a specific value
I have a document:
{
"_id":ObjectId("someID")
"email":"john#example.com"
}
I would like to retrieve "john#example.com" so that I can pass this value to the browser.
How do I do that?
I saw these SO posts, but I don't understand the solution at all:
How to get string value inside a Mongodb document?
How to get value from a MongoDB document