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Found 1349 Articles for MongoDB
435 Views
Let us create a collection with documents −> db.demo196.insertOne( ... { ... ... "Id" : "101", ... "details" : [ ... { ... "FirstName" : "Chris", ... "LastName" : "Brown", ... "Score" : 45 ... }, ... { ... "FirstName" : "David", ... "LastName" : "Miller", ... "Score" : 87 ... ... Read More
327 Views
To return a list of specific values, use map(). Let us create a collection with documents −> db.demo195.insertOne({"Subject":"MySQL"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3af3f203d395bdc21346d4") } > db.demo195.insertOne({"Subject":"MongoDB"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3af3f703d395bdc21346d5") } > db.demo195.insertOne({"Subject":"Java"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3af3fa03d395bdc21346d6") }Display all documents from a collection with the help of find() method −> db.demo195.find();This will produce the following output −{ "_id" : ObjectId("5e3af3f203d395bdc21346d4"), "Subject" : "MySQL" } { "_id" : ObjectId("5e3af3f703d395bdc21346d5"), "Subject" : "MongoDB" } { "_id" : ObjectId("5e3af3fa03d395bdc21346d6"), "Subject" : "Java" }Following is the query to return a ... Read More
133 Views
Let us first create a collection with documents −> db.demo194.insertOne( ... { ... "_id": 101, ... "details": { ... "otherDetails": { ... "List1": ["MongoDB", "MySQL"], ... "List2": ["Java"], ... "List3": ["MongoDB", "C"] ... } ... } ... } ...); { "acknowledged" : true, "insertedId" : 101 } > db.demo194.insertOne( {"_id": 102, "details": { "otherDetails": { "List1": ["Java", "C"], "List2": ["C++"], "List3": ["Python", "Spring"] } } } ... Read More
163 Views
To improve the execution time of a query, use index along with unique:true. Let us create a collection with documents −> db.demo193.createIndex({"LastName":1}, {unique:true}); { "createdCollectionAutomatically" : true, "numIndexesBefore" : 1, "numIndexesAfter" : 2, "ok" : 1 } > db.demo193.insertOne({"FirstName":"John", "LastName":"Doe"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3ade1803d395bdc21346d1") } > db.demo193.insertOne({"FirstName":"John", "LastName":"Smith"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3ade1f03d395bdc21346d2") } > db.demo193.insertOne({"FirstName":"David", "LastName":"Miller"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3ade2803d395bdc21346d3") }Display all documents from a collection with the help of find() method −> db.demo193.find();This will produce the following output −{ "_id" ... Read More
126 Views
To group several fields, use $group in MongoDB. Let us create a collection with documents −> db.demo192.insertOne({"Name":"Chris", "Age":22}); { "acknowledged" : true, "insertedId" : ObjectId("5e3adb9f03d395bdc21346cd") } > db.demo192.insertOne({"Name":"David", "Age":21}); { "acknowledged" : true, "insertedId" : ObjectId("5e3adba103d395bdc21346ce") } > db.demo192.insertOne({"Name":"Chris", "Age":22}); { "acknowledged" : true, "insertedId" : ObjectId("5e3adba503d395bdc21346cf") } > db.demo192.insertOne({"Name":"Mike", "Age":24}); { "acknowledged" : true, "insertedId" : ObjectId("5e3adbbf03d395bdc21346d0") }Display all documents from a collection with the help of find() method −> db.demo192.find();This will produce the following output −{ "_id" : ObjectId("5e3adb9f03d395bdc21346cd"), "Name" : "Chris", "Age" : 22 } { "_id" : ObjectId("5e3adba103d395bdc21346ce"), ... Read More
555 Views
To get values of cursor in MongoDB, use hasNext(). Let us create a collection with documents −> db.demo191.insertOne({"EmployeeId":1, "EmployeeName":"Chris Brown"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3ad95303d395bdc21346c5") } > db.demo191.insertOne({"EmployeeId":2, "EmployeeName":"David Miller"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3ad95f03d395bdc21346c6") } > db.demo191.insertOne({"EmployeeId":1, "EmployeeName":"John Doe"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3ad96803d395bdc21346c7") } > db.demo191.insertOne({"EmployeeId":1, "EmployeeName":"John Smith"}); { "acknowledged" : true, "insertedId" : ObjectId("5e3ad97003d395bdc21346c8") }Display all documents from a collection with the help of find() method −> db.demo191.find();This will produce the following output −{ "_id" : ObjectId("5e3ad95303d395bdc21346c5"), "EmployeeId" : 1, "EmployeeName" : "Chris ... Read More
471 Views
To implement aggregation with multiple keys, use aggregate() along with $group. Let us create a collection with documents −> db.demo190.insertOne( ... { ... ... "DueDate" : ISODate("2020-01-01"), ... "Value" : 10, ... "Name" : "Chris" ... } ...); { "acknowledged" : true, "insertedId" : ObjectId("5e3ad76403d395bdc21346bf") } > > db.demo190.insertOne( ... { ... ... "DueDate" : ISODate("2020-02-05"), ... "Value" : 30, ... "Name" : "David" ... } ...); { "acknowledged" : true, "insertedId" : ObjectId("5e3ad76403d395bdc21346c0") } > db.demo190.insertOne( ... { ... Read More
264 Views
To sort by the sum of specified object inside inner array, use $match along with $sort. Let us create a collection with documents −> db.demo189.insertOne( ... { ... "_id" : 100, ... "List" : [ ... { ... "Value" : 10 ... }, .. .{ ... "Value" : 20 ... }, ... { ... "Value" : 10 ... ... Read More
364 Views
To find same value multiple times, use $where in MongoDB. Let us create a collection with documents −> db.demo188.insertOne( ... { ... "ListOfData":[ ... {"Data": 100}, ... {"Data": 200}, ... {"Data": 100} ... ] ... } ...); { "acknowledged" : true, "insertedId" : ObjectId("5e3ad1c203d395bdc21346bd") } > db.demo188.insertOne( ... { ... "ListOfData":[ ... {"Data": 100}, ... {"Data": 200}, ... {"Data": 300} ... } ...); { ... Read More
126 Views
Let us first create a collection with documents −> db.demo187.insertOne( ... { ... "_id" : "101", ... "Details" : [ ... { "Subject" : "MongoDB" }, ... { "Subject" : "MySQL" } ... ] ... } ...); { "acknowledged" : true, "insertedId" : "101" } > db.demo187.insertOne( ... { ... "_id" : "102", ... "Details" : [ ... { } ... ] ... } ...); { "acknowledged" : true, "insertedId" : "102" ... Read More