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How to count a cursor’s iteration in MongoDB?
You need to use custom logic with the help of while loop along with find() cursor. Let us create a collection with documents −
> db.demo724.insertOne(
... {
... details:
... {
... id:101,
... otherDetails:[
... {Name:"Chris"}
... ]
... }
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5eab0cce43417811278f5890")
}
>
>
> db.demo724.insertOne(
... {
...
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5eab0cce43417811278f5891")
}
> db.demo724.insertOne(
... {
... details:
... {
... id:1001
... }
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5eab0cce43417811278f5892")
}Display all documents from a collection with the help of find() method −
> db.demo724.find();
This will produce the following output &miinus;
{ "_id" : ObjectId("5eab0cce43417811278f5890"), "details" : { "id" : 101, "otherDetails" : [ { "Name" : "Chris" } ] } }
{ "_id" : ObjectId("5eab0cce43417811278f5891") }
{ "_id" : ObjectId("5eab0cce43417811278f5892"), "details" : { "id" : 1001 } }Following is the query to count a cursor’s iteration in MongoDB −
> var c=db.demo724.find();
> var detailsCount=0;
> while (c.hasNext()) {
... var current = c.next();
... if (typeof current["details"] != "undefined") {
... detailsCount++;
... }
... }
1
> print("number of details: " + detailsCount);This will produce the following output −
number of details: 2
Updated on: 15-May-2020
135 Views
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