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Found 6702 Articles for Database
88 Views
You can use $push operator for this. Let us first create a collection with documents>db.twoSeparateArraysDemo.insertOne({"StudentName":"Larry", "StudentFirstGameScore":[98], "StudentSecondGameScore":[77]}); { "acknowledged" : true, "insertedId" : ObjectId("5c9b152815e86fd1496b38b8") } >db.twoSeparateArraysDemo.insertOne({"StudentName":"Mike", "StudentFirstGameScore":[58], "StudentSecondGameScore":[78]}); { "acknowledged" : true, "insertedId" : ObjectId("5c9b152d15e86fd1496b38b9") } >db.twoSeparateArraysDemo.insertOne({"StudentName":"David", "StudentFirstGameScore":[65], "StudentSecondGameScore":[67]}); { "acknowledged" : true, "insertedId" : ObjectId("5c9b153315e86fd1496b38ba") }Following is the query to display all documents from a collection with the help of find() method> db.twoSeparateArraysDemo.find().pretty();This will produce the following output{ "_id" : ObjectId("5c9b152815e86fd1496b38b8"), "StudentName" : "Larry", "StudentFirstGameScore" : [ 98 ], "StudentSecondGameScore" : [ ... Read More
98 Views
For conditional upserts or updates, you can use $max operator. Let us first create a collection with documents>db.conditionalUpdatesDemo.insertOne({"_id":100, "StudentFirstScore":89, "StudentSecondScore":78, "BiggestScore":89}); { "acknowledged" : true, "insertedId" : 100 } >db.conditionalUpdatesDemo.insertOne({"_id":101, "StudentFirstScore":305, "StudentSecondScore":560, "BiggestScore":1050}); { "acknowledged" : true, "insertedId" : 101 } >db.conditionalUpdatesDemo.insertOne({"_id":103, "StudentFirstScore":560, "StudentSecondScore":789, "BiggestScore":880}); { "acknowledged" : true, "insertedId" : 103 } Following is the query to display all documents from a collection with the help of find() method: > db.conditionalUpdatesDemo.find().pretty();This will produce the following output{ "_id" : 100, "StudentFirstScore" : 89, "StudentSecondScore" : 78, "BiggestScore" : 89 } { "_id" : 101, ... Read More
651 Views
Yes, you can use pull and add at the same time with $addToSet and $pull operator. Let us first create a collection with documents> db.pullAndAddToSetDemo.insertOne({StudentScores : [78, 89, 90]} ... ); { "acknowledged" : true, "insertedId" : ObjectId("5c9a797e15e86fd1496b38af") }Following is the query to display all documents from a collection with the help of find() method> db.pullAndAddToSetDemo.find().pretty();This will produce the following output{ "_id" : ObjectId("5c9a797e15e86fd1496b38af"), "StudentScores" : [ 78, 89, 90 ] }Following is the query to pull and addtoset at the same time in MongoDB> var ... Read More
921 Views
To find oldest/youngest post in MongoDB collection, you can use sort(). Let’s say you have a document with a field “UserPostDate” and you need to get the oldest and youngest post. For that, Let us first create a collection with documents>db.getOldestAndYoungestPostDemo.insertOne({"UserId":"Larry@123", "UserName":"Larry", "UserPostDate":new ISODate('2019-03-27 12:00:00')}); { "acknowledged" : true, "insertedId" : ObjectId("5c9a700f15e86fd1496b38ab") } >db.getOldestAndYoungestPostDemo.insertOne({"UserId":"Sam@897", "UserName":"Sam", "UserPostDate":new ISODate('2012-06-17 11:40:30')}); { "acknowledged" : true, "insertedId" : ObjectId("5c9a703815e86fd1496b38ac") } >db.getOldestAndYoungestPostDemo.insertOne({"UserId":"David@777", "UserName":"David", "UserPostDate":new ISODate('2018-01-31 10:45:35')}); { "acknowledged" : true, "insertedId" : ObjectId("5c9a705e15e86fd1496b38ad") } >db.getOldestAndYoungestPostDemo.insertOne({"UserId":"Chris@909", "UserName":"Chris", "UserPostDate":new ISODate('2017-04-14 04:12:04')}); { "acknowledged" : true, "insertedId" : ObjectId("5c9a708915e86fd1496b38ae") }Following ... Read More
116 Views
To increment a value inside a nested array, use positional operator ($). Let us first create a collection with documents> db.incrementInNestedArrayDemo.insertOne( ... { ... "StudentId":100, ... "ProjectDetails": ... [ ... {"ProjectId":567778888, ... "TeamSize":4 ... }, ... { ... "ProjectId":67888999, ... "TeamSize":2 ... } ... ] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5c9a6b7b15e86fd1496b38aa") }Following is the query to display all documents from a collection with the help ... Read More
635 Views
You can use upsert i.e. whenever you insert a value and it already exist then update would be performed. If the value does not already exist then it would get inserted.Let us first create a collection with documents> db.onlyInsertIfValueIsUniqueDemo.insertOne({"StudentName":"Larry", "StudentAge":22}); { "acknowledged" : true, "insertedId" : ObjectId("5c9a633815e86fd1496b38a4") } > db.onlyInsertIfValueIsUniqueDemo.insertOne({"StudentName":"Mike", "StudentAge":21}); { "acknowledged" : true, "insertedId" : ObjectId("5c9a634a15e86fd1496b38a5") } > db.onlyInsertIfValueIsUniqueDemo.insertOne({"StudentName":"Sam", "StudentAge":24}); { "acknowledged" : true, "insertedId" : ObjectId("5c9a635015e86fd1496b38a6") }Following is the query to display all documents from a collection with the help of find() method> db.onlyInsertIfValueIsUniqueDemo.find().pretty();This will produce the following output{ "_id" ... Read More
456 Views
Following is the syntax to count the number of documents in a MongoDB collectionlet anyVariableName= db.getCollection(‘yourCollectionName’); yourVariableName.count();Let us first create a collection with documents> db.countNumberOfDocumentsDemo.insertOne({"CustomerName":"Bob"}); { "acknowledged" : true, "insertedId" : ObjectId("5c9a5e2015e86fd1496b38a1") } >db.countNumberOfDocumentsDemo.insertOne({"CustomerName":"Ramit", "CustomerAge":23}); { "acknowledged" : true, "insertedId" : ObjectId("5c9a5e3515e86fd1496b38a2") } >db.countNumberOfDocumentsDemo.insertOne({"CustomerName":"Adam", "CustomerAge":27, "CustomerCountryName":"US"}); { "acknowledged" : true, "insertedId" : ObjectId("5c9a5e4c15e86fd1496b38a3") }Following is the query to display all documents from a collection with the help of find() method> db.countNumberOfDocumentsDemo.find().pretty();This will produce the following output{ "_id" : ObjectId("5c9a5e2015e86fd1496b38a1"), "CustomerName" : "Bob" } { "_id" : ObjectId("5c9a5e3515e86fd1496b38a2"), "CustomerName" : "Ramit", "CustomerAge" ... Read More
1K+ Views
Following is the syntax to return only a single property _id in MongoDBdb.yourCollectionName.find({}, {"_id": 1}).pretty();Let us first create a collection with documents> db.singlePropertyIdDemo.insertOne({"_id":101, "UserName":"Larry", "UserAge":21}); { "acknowledged" : true, "insertedId" : 101 } > db.singlePropertyIdDemo.insertOne({"_id":102, "UserName":"Mike", "UserAge":26}); { "acknowledged" : true, "insertedId" : 102 } > db.singlePropertyIdDemo.insertOne({"_id":103, "UserName":"Chris", "UserAge":24}); { "acknowledged" : true, "insertedId" : 103 } > db.singlePropertyIdDemo.insertOne({"_id":104, "UserName":"Robert", "UserAge":23}); { "acknowledged" : true, "insertedId" : 104 } > db.singlePropertyIdDemo.insertOne({"_id":105, "UserName":"John", "UserAge":27}); { "acknowledged" : true, "insertedId" : 105 }Following is the query to display all documents from a collection with the help of find() method> db.singlePropertyIdDemo.find().pretty();This will produce ... Read More
2K+ Views
Yes, it is possible to rename using aggregation. Let us first create a collection with documents> db.renameIdDemo.insertOne({"StudentName":"Chris"}); { "acknowledged" : true, "insertedId" : ObjectId("5c9a1760353decbc2fc927c5") } > db.renameIdDemo.insertOne({"StudentName":"Robert"}); { "acknowledged" : true, "insertedId" : ObjectId("5c9a1765353decbc2fc927c6") } > db.renameIdDemo.insertOne({"StudentName":"David"}); { "acknowledged" : true, "insertedId" : ObjectId("5c9a176b353decbc2fc927c7") }Following is the query to display all documents from a collection with the help of find() method> db.renameIdDemo.find();This will produce the following output{ "_id" : ObjectId("5c9a1760353decbc2fc927c5"), "StudentName" : "Chris" } { "_id" : ObjectId("5c9a1765353decbc2fc927c6"), "StudentName" : "Robert" } { "_id" : ObjectId("5c9a176b353decbc2fc927c7"), "StudentName" : "David" }Following is the query to ... Read More
120 Views
To query MongoDB with length criteria, you can use regex. Following is the syntaxdb.yourCollectionName.find({ ‘yourFieldName’: { $regex: /^.{yourLengthValue1, yourLengthValue2}$/ } });Let us create a collection with documents. Following is the query> db.queryLengthDemo.insertOne({"StudentFullName":"John Smith"}); { "acknowledged" : true, "insertedId" : ObjectId("5c9a01ae353decbc2fc927c0") } > db.queryLengthDemo.insertOne({"StudentFullName":"John Doe"}); { "acknowledged" : true, "insertedId" : ObjectId("5c9a01b4353decbc2fc927c1") } > db.queryLengthDemo.insertOne({"StudentFullName":"David Miller"}); { "acknowledged" : true, "insertedId" : ObjectId("5c9a01c2353decbc2fc927c2") } > db.queryLengthDemo.insertOne({"StudentFullName":"Robert Taylor"}); { "acknowledged" : true, "insertedId" : ObjectId("5c9a01e2353decbc2fc927c3") } > db.queryLengthDemo.insertOne({"StudentFullName":"Chris Williams"}); { "acknowledged" : true, "insertedId" : ObjectId("5c9a01f1353decbc2fc927c4") }Following is the query to display ... Read More