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Found 1659 Articles for Big Data Analytics
4K+ Views
To fund a value from JSON data, use the find() along with dot(.) notation. Let us first create a collection with documents −> db.findValueFromJsonDemo.insertOne( { "UserDetails": [{ "_id": new ObjectId(), "UserName": "Carol", "UserMessage": "Hi" }], "UserFriendsName": ["John", "Sam"] } ); { "acknowledged" : true, "insertedId" : ObjectId("5cdf8a4cbf3115999ed511fd") }Following is the query to display all documents from a collection with the help of find() method −> db.findValueFromJsonDemo.find().pretty();This will produce the following output −{ "_id" : ... Read More
208 Views
Use the $slice operator. Let us first create a collection with documents −> db.limitAndSliceProjectionDemo.insertOne( { "_id" : 101, "UserName" : "Carol", "UserAge" : 26, "UserMesssage" : [ "Hi", "Hello", "Bye", "Awesome", "Good", "Bad", "Nice", "Good Night", "Good Morning" ] } ); { "acknowledged" : true, "insertedId" : ... Read More
2K+ Views
Use the $push operator to add a sub-document. Let us first create a collection with documents −> db.subDocumentToSubDocumentDemo.insertOne( { "_id" :101, "StudentName" : "Larry", "StudentAge" : 21, "StudentDetails" : [ { "StudentCountryName" : "US", "StudentFavouriteSubjectList" : [ ] } ] } ); { "acknowledged" : true, "insertedId" : 101 }Following is the query to display all documents from a collection with the help ... Read More
339 Views
For this, use the $size operator. Let us first create a collection with documents −> db.checkIfListIsNotEmptyDemo.insertOne({"UserFriendGroup":["John", "David"]}); { "acknowledged" : true, "insertedId" : ObjectId("5cdd99e8bf3115999ed511f7") } > db.checkIfListIsNotEmptyDemo.insertOne({"UserFriendGroup":["Carol"]}); { "acknowledged" : true, "insertedId" : ObjectId("5cdd99e9bf3115999ed511f8") } > db.checkIfListIsNotEmptyDemo.insertOne({"UserFriendGroup":[]}); { "acknowledged" : true, "insertedId" : ObjectId("5cdd99ebbf3115999ed511f9") } > db.checkIfListIsNotEmptyDemo.insertOne({"UserFriendGroup":[null]}); { "acknowledged" : true, "insertedId" : ObjectId("5cdd99f2bf3115999ed511fa") } > db.checkIfListIsNotEmptyDemo.insertOne({"UserFriendGroup":[]}); { "acknowledged" : true, "insertedId" : ObjectId("5cdd99f6bf3115999ed511fb") }Following is the query to display all documents from a collection with the help of find() method −> db.checkIfListIsNotEmptyDemo.find().pretty();This will produce the following output −{ ... Read More
2K+ Views
Let’s say you have saved the Login date of users. Now, you want the count of records for specific date only i.e. login date. For this, use $gte and $lt operator along with count(). Let us first create a collection with documents −> db.findDataByDateDemo.insertOne({"UserName":"John", "UserLoginDate":new ISODate("2019-01-31")}); { "acknowledged" : true, "insertedId" : ObjectId("5cdd8cd7bf3115999ed511ed") } > db.findDataByDateDemo.insertOne({"UserName":"Larry", "UserLoginDate":new ISODate("2019-02-01")}); { "acknowledged" : true, "insertedId" : ObjectId("5cdd8ce7bf3115999ed511ee") } > db.findDataByDateDemo.insertOne({"UserName":"Sam", "UserLoginDate":new ISODate("2019-05-02")}); { "acknowledged" : true, "insertedId" : ObjectId("5cdd8cf3bf3115999ed511ef") } > db.findDataByDateDemo.insertOne({"UserName":"David", "UserLoginDate":new ISODate("2019-05-16")}); { "acknowledged" : true, "insertedId" : ObjectId("5cdd8d00bf3115999ed511f0") } > db.findDataByDateDemo.insertOne({"UserName":"Carol", ... Read More
183 Views
If you will try to use the method drop(), then it will delete all information about the collection. Indexing is fast. However, if you will use the method remove(), then it removes all records but keeps the collection and indexes.Let us check with the help of example.Using drop()Let us first create a collection with documents −> db.dropWorkingDemo.createIndex({"FirstName":1}); { "createdCollectionAutomatically" : true, "numIndexesBefore" : 1, "numIndexesAfter" : 2, "ok" : 1 } > db.dropWorkingDemo.insertOne({"FirstName":"John"}); { "acknowledged" : true, "insertedId" : ObjectId("5cdd8742bf3115999ed511e9") }Following is the query to display all documents from a collection with the ... Read More
265 Views
You can use $where operator for this. Let us first create a collection with documents −> db.sumOfFieldIsGreaterThanDemo.insertOne({"Price1":10, "Price2":50, "Price3":40}); { "acknowledged" : true, "insertedId" : ObjectId("5cdd84b8bf3115999ed511e6") } > db.sumOfFieldIsGreaterThanDemo.insertOne({"Price1":11, "Price2":1, "Price3":120}); { "acknowledged" : true, "insertedId" : ObjectId("5cdd84c6bf3115999ed511e7") } > db.sumOfFieldIsGreaterThanDemo.insertOne({"Price1":10, "Price2":9, "Price3":6}); { "acknowledged" : true, "insertedId" : ObjectId("5cdd84d2bf3115999ed511e8") }Following is the query to display all documents from a collection with the help of find() method −> db.sumOfFieldIsGreaterThanDemo.find();This will produce the following output −{ "_id" : ObjectId("5cdd84b8bf3115999ed511e6"), "Price1" : 10, "Price2" : 50, "Price3" : 40 } { "_id" : ObjectId("5cdd84c6bf3115999ed511e7"), "Price1" : ... Read More
830 Views
You can use $elemMatch operator for this. Let us first create a collection with documents −> db.pushNewItemsDemo.insertOne( { "_id" :1, "StudentScore" : 56, "StudentOtherDetails" : [ { "StudentName" : "John", "StudentFriendName" : [ "Bob", "Carol" ] }, { "StudentName" : ... Read More
328 Views
You need to use multi:true to update multiple documents. Let us first create a collection with documents −> db.multiUpdateDemo.insertOne({"ClientName":"John", "ClientAge":29}); { "acknowledged" : true, "insertedId" : ObjectId("5cda5bc0b50a6c6dd317adc8") } > db.multiUpdateDemo.insertOne({"ClientName":"Carol", "ClientAge":31}); { "acknowledged" : true, "insertedId" : ObjectId("5cda5bc1b50a6c6dd317adc9") } > db.multiUpdateDemo.insertOne({"ClientName":"John", "ClientAge":39}); { "acknowledged" : true, "insertedId" : ObjectId("5cda5bc3b50a6c6dd317adca") } > db.multiUpdateDemo.insertOne({"ClientName":"John", "ClientAge":41}); { "acknowledged" : true, "insertedId" : ObjectId("5cda5bc5b50a6c6dd317adcb") } > db.multiUpdateDemo.insertOne({"ClientName":"David", "ClientAge":35}); { "acknowledged" : true, "insertedId" : ObjectId("5cda5bc6b50a6c6dd317adcc") }Following is the query to display all documents from a collection with the help of find() method −> db.multiUpdateDemo.find().pretty();This ... Read More
224 Views
You can use $set operator for this. Following is the syntax −db.yourCollectionName.update({"_id" : yourObjectId }, {$set: { "yourOuterFieldName.anyInnerFieldName": yourValue}});Let us first create a collection with documents −> db.pushNewKeyDemo.insertOne({"UserId":100, "UserDetails":{}}); { "acknowledged" : true, "insertedId" : ObjectId("5cda58f5b50a6c6dd317adbf") }Following is the query to display all documents from a collection with the help of find() method −> db.pushNewKeyDemo.find();This will produce the following output −{ "_id" : ObjectId("5cda58f5b50a6c6dd317adbf"), "UserId" : 100, "UserDetails" : { } }Following is the query to push new key element into subdocument of MongoDB −> db.pushNewKeyDemo.update({"_id" : ObjectId("5cda58f5b50a6c6dd317adbf")}, {$set: { "UserDetails.UserName": "David Miller"}}); WriteResult({ "nMatched" : 1, ... Read More