I have an array inside a collection in mongodb as per below.
{
"_id" : ObjectId("53dbb05fa976627439d43884"),
"employee" : [
{
"date" : "1986-03-10"
},
{
"date" : "1986-12-11"
}
]
}
Now I want to find all distinct date and output it to array in nodejs format.
var collection = db.collection('employee');
collection.distinct('employee.date').toArray(function(err, docsa) {
console.log(docsa);
});
};
The problem is I will receive the following error, but those collection.distinct command can be run on mongodb.Anyhow I can avoid the error ?
TypeError: Cannot call method 'toArray' of undefined
Or is there any way I can use collection.find() to get the same output?
you try collection.distinct('employee.data'), on a collection called 'employee'. I believe you want :
collection.distinct('date')
Related
I have built an API that updates records in MongoDB using mongoose, but currently what happening is if I am passing only 4 field values in the JSON file of postman and try to update then all the values are updating with value null except that 4 fields which I had passed in JSON so can anyone help me how I can pass dynamic field and value that update only passed values of collection not all the fields of collection.
Passes JSON :
{
"preferance_id" : "60fe9ba1766d10d65c64083c",
"is_active": true,
"price_blur":true,
"affiliate_commission":27,
"language_code": "en"
}
Update call which I have passed in node js
transaction.update(PreferencesMasterName,
{ _id: new mongoose.Types.ObjectId(preferance_id) }, {
subscriptin_vat : subscriptin_vat,
popular_normal : popular_normal,
popular_crawled : popular_crawled,
price_blur : price_blur,
blur_rule : blur_rule,
affiliate_commission : affiliate_commission,
red_lock : red_lock,
automatic_dummy_price : automatic_dummy_price,
...
is_active: is_active
})
I want to pass dynamic field and values here instead of this because due to this other values are set will null value. So, can anyone have an idea how to do this?
You can do something like this:
const data = res.body; // should be an object that needs to updated
transaction.update({_id: PreferanceMasterName._id}, data, {new: true }, ( error, obj ) => {
if( error ) {
console.error( JSON.stringify( error ) );
}
console.log( obj );
});
In certain cases new doesn't work, you can use : { returnOriginal: false };
for more details, you can check this thread there are multiple ways you can do this.
Please check update how to use it.
I am new to MongoDB and I need to apply a regex to the find method using NodeJS Mongoose. The db contains elements such as:
{
"_id" : ObjectId("1234567899788675432454677"),
"nodes" : "[{\"name\":\"BINS\",\"oxygenation\":7.8,\"oxygenSaturation\":86,\"temperature\":13.3},{\"name\":\"CEST\",\"oxygenation\":4.6,\"oxygenSaturation\":52,\"temperature\":14.7},
"orp" : "0",
"chlorophyll" : "0",
"date" : "1615995776000",
"__v" : 0 }
and I need to go inside the nodes string to get all "name" values (in the example BINS and CEST). The regex that allows me to do it is
/(?<=name\\\"\:\\")\w+(?=\\)/gm
but I get errors when trying to use it both in mongo and Mongoose. For mongo I tried to escape all special characters:
db.my_collection.find( { nodes: { $regex: "\(\?<=\\\"name\\\": \\\"\)\\w\+\(\?=\\\\\)" } } )
but I get an empty result.
On Mongoose I tried several escaping such as the following, but I always get an error of invalid regex.
db.my_collection.find({ nodes : { $regex : '\(?<=name\\\\\\\"\\:\\\\\"\)\\w+\(?=\\\\\)' } }).
exec(function (err, waterSensorsReadings) { ... });
I am using MEAN stack, i have an entry like this in my mongodb
{ "_id" : ObjectId("5577467683f4716018db19ed"),
"requestMatrix" : { "1698005072" : { "rideId" : "641719948", "status" :"accepted" },"1698005073" : { "rideId" : "641719545", "status" :"rejected" } },
"partners":[ { "customerNumber" : 1698005072 }, { "customerNumber" : 1698072688 } ]}
I want to query the db to return me this entire document based on whether the status is accepted or rejected.
When I run the below query in a command prompt, i get the expected answer
db.joinedrides.find({'requestMatrix.1698005072.status':"accepted"})
But when i want to do the same from nodeJs, I am stuck as the number 1698005072 in the above query is a variable, i am not able to write a query for that.
tried something like this
var criteria = "'requestMatrix.'"+customerNumber+"'.status'";
JoinedRide.find({criteria:"accepted"},function(err,joinedRides){
})
where customerNumber will vary for different requests, in the above mentioned case its value is 1698005072
Any help is appreciated.
You need to do something like this:
var query = {};
var criteria = "requestMatrix." + customerNumber + ".status";
query[criteria] = "accepted"
JoinedRide.find(query,function(err,joinedRides){
})
I'm using mongify to migrate a mysql database into mongodb.
Doing that, 2 questions appeared:
1- How can i declare my translation file in order to have a embedded array of ids that references to the objects (that are stored in a different collection and can be retrieved through populate), instead of just embedding as json objects.
2- Embedded objects can have an unique id as objects in colections do?. On other projects i've used that approach to query for embedded objects, but if that id is not present i should use a different field.
Unfortunately the first request isn't possible with Mongify at the moment, it requires a custom script to do that.
I could give you more details if you want to send me your translation file (Make sure to remove any sensitive data).
As for number two, the embedded object will get a unique ID. You don't need to do anything special.
Hope that answers your questions.
from mongify isn't possible but in mongodb you can transform data as follows:
//find posts has array of objects
db.getCollection('posts').find({'_tags.0': {$exists: true}}).forEach( function (post) {
var items = [];
var property = '_tags';
post[property].forEach(function(element){
if(element._id !== undefined){
items.push(element._id);
}
});
if(items.length>0){
post[property] = items;
db.posts.update({_id:post._id},post);
}
});
Source Document:
{
"_id" : ObjectId("576aa0389863482f64051c81"),
"id_post" : 130155,
"_tags" : [
{
"_id" : ObjectId("576a9efd9863482f64000044")
},
{
"_id" : ObjectId("576a9efd9863482f6400004b")
},
{
"_id" : ObjectId("576a9efd9863482f64000052")
},
{
"_id" : ObjectId("576a9efd9863482f6400005a")
}
]
}
Final Document:
{
"_id" : ObjectId("576aa0389863482f64051c81"),
"id_post" : 130155,
"_tags" : [
ObjectId("576a9efd9863482f64000044"),
ObjectId("576a9efd9863482f6400004b"),
ObjectId("576a9efd9863482f64000052"),
ObjectId("576a9efd9863482f6400005a")
]
}
I am using node and mongo with the native client.
I would like to add pagination to my application.
To get pagination, I need my responses to always return count alongside data
I would like to get something like:
{
count : 111,
data : [ { 'a' : 'only first item was requested' } ]
}
I can do this in mongo
> var guy = db.users.find({}).limit(1)
> guy.count()
11
> guy.toArray()
[
{
"_id" : ObjectId("5381a7c004fb02b10b557ee3"),
"email" : "myEmail#guy.com",
"fullName" : "guy mograbi",
"isAdmin" : true,
"password" : "fe20a1f102f49ce45d1170503b4761ef277bb6f",
"username" : "guy",
"validated" : true
}
]
but when I do the same with nodejs mongo client I get errors.
var cursor = collection.find().limit(1);
cursor.toArray( function(){ .. my callback .. });
cursor.count();
It seems that
count is not defined on cursor
that once I applied toArray on cursor, I cannot use the cursor again
How, using nodejs, can I accomplish the same thing I can with mongo directly?
As others have said, if you want to have a total count of the items and then the data you will need to have two queries, there is no other way. Why are you concerned with creating two queries?