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Found 1359 Articles for MongoDB
326 Views
Let us create a collection with documents −> db.demo590.insert([ ... { "Name": "Chris", "Age": 21 }, ... {"Name": "Bob", "Age": 20}, ... { "Name": "Sam", "Age": 19 } ... ]); BulkWriteResult({ "writeErrors" : [ ], "writeConcernErrors" : [ ], "nInserted" : 3, "nUpserted" : 0, "nMatched" : 0, "nModified" : 0, "nRemoved" : 0, "upserted" : [ ] })Display all documents from a collection with the help of find() method −> db.demo590.find();This will produce the following output −{ "_id" : ObjectId("5e92d514fd2d90c177b5bcd0"), "Name" : "Chris", "Age" : 21 } { ... Read More
113 Views
To check equality and fetch the documents, use $where in MongoDB. Let us create a collection with documents −> db.demo589.insertOne({deliveryAddress:"US", billingAddress:"UK"});{ "acknowledged" : true, "insertedId" : ObjectId("5e92c117fd2d90c177b5bccc") } > db.demo589.insertOne({deliveryAddress:"US", billingAddress:"US"});{ "acknowledged" : true, "insertedId" : ObjectId("5e92c11bfd2d90c177b5bccd") } > db.demo589.insertOne({deliveryAddress:"US", billingAddress:"AUS"});{ "acknowledged" : true, "insertedId" : ObjectId("5e92c11ffd2d90c177b5bcce") } > db.demo589.insertOne({deliveryAddress:"UK", billingAddress:"US"});{ "acknowledged" : true, "insertedId" : ObjectId("5e92c127fd2d90c177b5bccf") }Display all documents from a collection with the help of find() method −> db.demo589.find();This will produce the following output −{ "_id" : ObjectId("5e92c117fd2d90c177b5bccc"), "deliveryAddress" : "US", "billingAddress" : "UK" } { "_id" : ObjectId("5e92c11bfd2d90c177b5bccd"), "deliveryAddress" : "US", "billingAddress" : ... Read More
189 Views
To gather a unique array items, use distinct(). Let us create a collection with documents −> db.demo588.insertOne({"CountryName":["US","AUS","UK","US","UK","AUS"]});{ "acknowledged" : true, "insertedId" : ObjectId("5e92bbd2fd2d90c177b5bccb") }Display all documents from a collection with the help of find() method −> db.demo588.find().pretty();This will produce the following output −{ "_id" : ObjectId("5e92bbd2fd2d90c177b5bccb"), "CountryName" : [ "US", "AUS", "UK", "US", "UK", "AUS" ] }Following is the query to gather unique array item −> db.demo588.distinct("CountryName");This will produce the following output −[ "AUS", "UK", "US" ]
96 Views
To append subdocuments, use $push in MongoDB. The update() is used to update. Let us create a collection with documents −> db.demo587.insertOne({"id":101, "details":[{Name:"Chris", Age:21, Marks:57}]});{ "acknowledged" : true, "insertedId" : ObjectId("5e92ba01fd2d90c177b5bcc9") } > db.demo587.insertOne({"id":102, "details":[{Name:"Bob", Age:22, Marks:78}]});{ "acknowledged" : true, "insertedId" : ObjectId("5e92ba0efd2d90c177b5bcca") }Display all documents from a collection with the help of find() method −> db.demo587.find();This will produce the following output −{ "_id" : ObjectId("5e92ba01fd2d90c177b5bcc9"), "id" : 101, "details" : [ { "Name" : "Chris", "Age" : 21, "Marks" : 57 } ] } { "_id" : ObjectId("5e92ba0efd2d90c177b5bcca"), "id" : 102, "details" : [ { "Name" : ... Read More
835 Views
Let us create a collection with documents −> db.demo586.insertOne( ... {"details": [ ... { ... "Name":"Chris", ... "Marks":71 ... }, ... { ... "Name":"Chris", ... "Marks":61 ... }, ... { ... "Name":"David", ... "Marks":81 ... } ... ... ] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5e9200fefd2d90c177b5bcc7") } > db.demo586.insertOne( ... Read More
181 Views
To manually add value, use $push in MongoDB. Let us create a collection with documents −> db.demo585.insert({ ... firstName: 'John', ... lastName: 'Doe', ... SubjectName:"MongoDB", ... Marks: [59] ... }); WriteResult({ "nInserted" : 1 }) > db.demo585.insert({ ... firstName: 'Chris', ... lastName: 'Brown', ... SubjectName:"MySQL", ... Marks: [79] ... }); WriteResult({ "nInserted" : 1 })Display all documents from a collection with the help of find() method−> db.demo585.find();This will produce the following output −{ "_id" : ObjectId("5e91fd80fd2d90c177b5bcc3"), "firstName" : "John", "lastName" : "Doe", "SubjectName" : "MongoDB", "Marks" : [ 59 ] } { ... Read More
65 Views
Let us first create a document −> var document= [ ... { "SubjectName" : "MySQL", "Marks" : 78 }, ... { "SubjectName" : "MongoDB", "Marks" : 89 }, ... { "SubjectName" : "Java", "Marks" : 71 }, ... ];Following is the query to display document −> printjson(document);This will produce the following output −[ { "SubjectName" : "MySQL", "Marks" : 78 }, { "SubjectName" : "MongoDB", "Marks" : 89 }, { "SubjectName" : "Java", "Marks" : 71 } ]Following is the query to project grouping into an object in MongoDB −> var makeObject= {}; > document.forEach(function (d){ ... makeObject[d.SubjectName] = d.Marks; ... }); > printjson(makeObject);This will produce the following output −{ "MySQL" : 78, "MongoDB" : 89, "Java" : 71 }
787 Views
To get an average of array elements, use $avg. Let us create a collection with documents −> db.demo584.insertOne({"Marks":[75,50,85,60,80]});{ "acknowledged" : true, "insertedId" : ObjectId("5e91d827fd2d90c177b5bcc2") }Display all documents from a collection with the help of find() method −> db.demo584.find().pretty();This will produce the following output −{ "_id" : ObjectId("5e91d827fd2d90c177b5bcc2"), "Marks" : [ 75, 50, 85, 60, 80 ] }Following is the query to find avg in the aggregation of array element −> db.demo584.aggregate([ ... { $project: { MarksAvg: { $avg: "$Marks"} } } ... ])This will produce the following output −{ "_id" : ObjectId("5e91d827fd2d90c177b5bcc2"), "MarksAvg" : 70 }
100 Views
The accumulators are operators that maintain their state as documents progress through the pipeline.The $ROOT references the root document, i.e. the top-level document, currently being processed in the aggregation pipeline stage.Let us create a collection with documents −> db.demo582.insertOne({FirstName:"Chris", Age:21, createDate:new ISODate("2020-01-10")});{ "acknowledged" : true, "insertedId" : ObjectId("5e91ce41fd2d90c177b5bcbd") } > db.demo582.insertOne({FirstName:"Chris", Age:21, createDate:new ISODate("2020-04-21")});{ "acknowledged" : true, "insertedId" : ObjectId("5e91ce4ffd2d90c177b5bcbe") } > db.demo582.insertOne({FirstName:"Chris", Age:22, createDate:new ISODate("2020-02-11")});{ "acknowledged" : true, "insertedId" : ObjectId("5e91ce59fd2d90c177b5bcbf") } > db.demo582.insertOne({FirstName:"Chris", Age:22, createDate:new ISODate("2020-01-12")});{ "acknowledged" : true, "insertedId" : ObjectId("5e91ce6efd2d90c177b5bcc0") }Display all documents from a collection with the help of find() method ... Read More
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