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Found 6702 Articles for Database
128 Views
For this, use the $exists operator. Let us first create a collection with documents −>dbfindDocumentContainsSpecificFieldDemoinsertOne({"ProductPrices":{"Product1":10, "Pr oduct2":50}}); { "acknowledged" : true, "insertedId" : ObjectId("5cf2385bb64a577be5a2bc14") } >dbfindDocumentContainsSpecificFieldDemoinsertOne({"ProductPrices":{"Product3":150, "P roduct7":100, "Product5":250}}); { "acknowledged" : true, "insertedId" : ObjectId("5cf2387eb64a577be5a2bc15") }Following is the query to display all documents from a collection with the help of find() method −> dbfindDocumentContainsSpecificFieldDemofind()pretty();This will produce the following document −{ "_id" : ObjectId("5cf2385bb64a577be5a2bc14"), "ProductPrices" : { "Product1" : 10, "Product2" : 50 } } { "_id" : ObjectId("5cf2387eb64a577be5a2bc15"), "ProductPrices" : { ... Read More
318 Views
Use $slice operator for this. Let us first create a collection with documents −> db.gettingFirstItemInArrayDemo.insertOne( { "UserId": 101, "UserName":"Carol", "UserOtherDetails": [ {"UserFriendName":"Sam"}, {"UserFriendName":"Mike"}, {"UserFriendName":"David"}, {"UserFriendName":"Bob"} ] } ); { "acknowledged" : true, "insertedId" : ObjectId("5cdfca52bf3115999ed51205") }Following is the query to display all documents from a collection with the help of find() method −> db.gettingFirstItemInArrayDemo.find().pretty();This will produce the following output −{ "_id" : ObjectId("5cdfca52bf3115999ed51205"), "UserId" : 101, ... Read More
110 Views
For this, use MongoDB $substr. Let us first create a collection with documents −> dblimitTheNumberOfCharactersDemoinsertOne({"Title":"MongoDB is No SQL database"}); { "acknowledged" : true, "insertedId" : ObjectId("5cf23013b64a577be5a2bc0e") } > dblimitTheNumberOfCharactersDemoinsertOne({"Title":"MySQL is a relational database"}); { "acknowledged" : true, "insertedId" : ObjectId("5cf2302db64a577be5a2bc0f") } Following is the query to display all documents from a collection with the help of find() method −> dblimitTheNumberOfCharactersDemofind()pretty();This will produce the following document −{ "_id" : ObjectId("5cf23013b64a577be5a2bc0e"), "Title" : "MongoDB is No SQL database" } { "_id" : ObjectId("5cf2302db64a577be5a2bc0f"), "Title" : "MySQL is a relational database" }Following is the ... Read More
186 Views
You can use pop() for this. Let us first create a collection with documents −> db.persistChangeDemo.insertOne({"Name" : "Larry", "CreditScore": [500, 700, 760, 100]}); { "acknowledged" : true, "insertedId" : ObjectId("5cdfc52cbf3115999ed51203") }Following is the query to display all documents from a collection with the help of find() method −> db.persistChangeDemo.find().pretty();This will produce the following output −{ "_id" : ObjectId("5cdfc52cbf3115999ed51203"), "Name" : "Larry", "CreditScore" : [ 500, 700, 760, 100 ] }Following is the query to pop a value −> myDocument.CreditScore.pop(); 100Let us save ... Read More
963 Views
We will use printjson() for this. Let us first create a collection with documents −> dbprintResultScriptDemoinsertOne({"StudentName":"John", "StudentAge":21}); { "acknowledged" : true, "insertedId" : ObjectId("5cf22c02b64a577be5a2bc0b") } > dbprintResultScriptDemoinsertOne({"StudentName":"Carol", "StudentAge":20}); { "acknowledged" : true, "insertedId" : ObjectId("5cf22c09b64a577be5a2bc0c") } > dbprintResultScriptDemoinsertOne({"StudentName":"David", "StudentAge":19}); { "acknowledged" : true, "insertedId" : ObjectId("5cf22c11b64a577be5a2bc0d") }Following is the query to display all documents from a collection with the help of find() method −> dbprintResultScriptDemofind();This will produce the following document −{ "_id" : ObjectId("5cf22c02b64a577be5a2bc0b"), "StudentName" : "John", "StudentAge" : 21 } { "_id" : ObjectId("5cf22c09b64a577be5a2bc0c"), "StudentName" : "Carol", "StudentAge" : 20 } { "_id" ... Read More
300 Views
For this, use the $addToSet operator. Let us first create a collection with documents −> db.findDocumentWithCommonFieldsDemo.insertOne( { "UserId":1, "UserName":"Carol" } ); { "acknowledged" : true, "insertedId" : ObjectId("5cdf8ebebf3115999ed51200") } > db.findDocumentWithCommonFieldsDemo.insertOne( { "UserId":2, "UserName":"David" } ); { "acknowledged" : true, "insertedId" : ObjectId("5cdf8ebebf3115999ed51201") } > > db.findDocumentWithCommonFieldsDemo.insertOne( { "UserId":1, "UserName":"Sam" } ); { "acknowledged" : true, "insertedId" : ObjectId("5cdf8ebebf3115999ed51202") }Following is the query to display all documents from a collection ... Read More
129 Views
To compare multiple properties, use the $where operator. Let us first create a collection with documents −> dbcomparingMultiplePropertiesDemoinsertOne({"Values":[10, 70, 60]}); { "acknowledged" : true, "insertedId" : ObjectId("5cf228fcb64a577be5a2bc0a") }Following is the query to display all documents from a collection with the help of find() method −> dbcomparingMultiplePropertiesDemofind()pretty();This will produce the following document −{ "_id" : ObjectId("5cf228fcb64a577be5a2bc0a"), "Values" : [ 10, 70, 60 ] }Case 1: If condition becomes true then you will get an array otherwise nothing will get displayed Following is the query to compare multiple ... Read More
83 Views
Let us first create a collection with documents −> dbworkingOfRegularExpressionDemoinsertOne({ "StudentDetails" : { "StudentName" : "John" }, "StudentAge":21 }); { "acknowledged" : true, "insertedId" : ObjectId("5cf227acb64a577be5a2bc07") } > dbworkingOfRegularExpressionDemoinsertOne({ "StudentDetails" : { "StudentName" : "JOHN" }, "StudentAge":19 }); { "acknowledged" : true, "insertedId" : ObjectId("5cf227b8b64a577be5a2bc08") } > dbworkingOfRegularExpressionDemoinsertOne({ "StudentDetails" : { "StudentName" : "Carol" }, "StudentAge":20 }); { "acknowledged" : true, "insertedId" : ObjectId("5cf227c2b64a577be5a2bc09") }Following is the query to display all documents from a collection with the help of find() method −> dbworkingOfRegularExpressionDemofind();This will produce the following document −{ "_id" : ObjectId("5cf227acb64a577be5a2bc07"), "StudentDetails" : ... Read More
131 Views
To delete specific record, use $pull operator. Let us first create a collection with documents −> dbdeletingSpecificRecordDemoinsertOne( { "StudentDetails": [ { "StudentName": "John", "StudentSubjectDetails": [ { "Subject": "MongoDB", "Marks":45 }, { "Subject": ... Read More
162 Views
Use aggregation for this and add the values to an array using the $group and $addToSet operatorLet us first create a collection with documents −> dbspecifyReturnFormatDemoinsertOne({"Subject":"MongoDB"}); { "acknowledged" : true, "insertedId" : ObjectId("5cefd364ef71edecf6a1f6c0") } > dbspecifyReturnFormatDemoinsertOne({"Subject":"MySQL"}); { "acknowledged" : true, "insertedId" : ObjectId("5cefd369ef71edecf6a1f6c1") } > dbspecifyReturnFormatDemoinsertOne({"Subject":"SQL Server"}); { "acknowledged" : true, "insertedId" : ObjectId("5cefd36fef71edecf6a1f6c2") }Following is the query to display all documents from a collection with the help of find() method −> dbspecifyReturnFormatDemofind();Output{ "_id" : ObjectId("5cefd364ef71edecf6a1f6c0"), "Subject" : "MongoDB" } { "_id" : ObjectId("5cefd369ef71edecf6a1f6c1"), "Subject" : "MySQL" } { "_id" : ObjectId("5cefd36fef71edecf6a1f6c2"), "Subject" : ... Read More