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Found 1659 Articles for Big Data Analytics
146 Views
For this, use UPDATE() method and within that set the two conditions. Let us create a collection with documents −> db.demo605.insertOne( ... { ... _id:1, ... "Information" : [ ... { ... "id" : "Product-1", ... "Quantity" : 50, ... }, ... { ... "id" : "Product-2", ... "Quantity" : 100, ... }, ... Read More
3K+ Views
For this, set “unique:true” i.e. the unique constraint and avoid inserting duplicates as in the below syntax −db.yourCollectionName.ensureIndex({yourFieldName: 1}, {unique: true, dropDups: true})To understand the above syntax, let us create a collection with documents. Here, duplicate insertion won’t be allowed −> db.demo604.ensureIndex({FirstName: 1}, {unique: true, dropDups: true});{ "createdCollectionAutomatically" : true, "numIndexesBefore" : 1, "numIndexesAfter" : 2, "ok" : 1 } > db.demo604.insertOne({FirstName:"Chris"});{ "acknowledged" : true, "insertedId" : ObjectId("5e960887ed011c280a0905d8") } > db.demo604.insertOne({FirstName:"Bob"});{ "acknowledged" : true, "insertedId" : ObjectId("5e96088aed011c280a0905d9") } > db.demo604.insertOne({FirstName:"David"});{ "acknowledged" : true, "insertedId" : ObjectId("5e96088ded011c280a0905da") } > db.demo604.insertOne({FirstName:"Chris"}); 2020-04-15T00:31:35.978+0530 ... Read More
215 Views
The NumberLong(x) goes beyond its limit value and round off the value whereas NumberLong(“x”) does not.Now, we will consider a number and would use it for both NumberLong(x) and NumberLong(“x”) to see the difference.Let us create a collection with documents −> db.demo603.insert({"longValue" : NumberLong(988998985857575789)}); WriteResult({ "nInserted" : 1 }) > db.demo603.insert({"longValueInString" : NumberLong("988998985857575789")});Display all documents from a collection with the help of find() method −> db.demo603.find().pretty();This will produce the following output −{ "_id" : ObjectId("5e9605e5ed011c280a0905d1"), "longValue" : NumberLong("988998985857575808") } { "_id" : ObjectId("5e9605faed011c280a0905d2"), "longValueInString" : NumberLong("988998985857575789") }
589 Views
For such grouping of documents, use $group in MongoDB aggregate(). Let us create a collection with documents −> db.demo602.insertOne({id:1, Name:"Chris"});{ "acknowledged" : true, "insertedId" : ObjectId("5e960080ed011c280a0905c9") } > db.demo602.insertOne({id:2, Name:"David"});{ "acknowledged" : true, "insertedId" : ObjectId("5e960086ed011c280a0905ca") } > db.demo602.insertOne({id:1, Name:"Bob"});{ "acknowledged" : true, "insertedId" : ObjectId("5e96008ced011c280a0905cb") } > db.demo602.insertOne({id:3, Name:"Mike"});{ "acknowledged" : true, "insertedId" : ObjectId("5e960092ed011c280a0905cc") } > db.demo602.insertOne({id:2, Name:"John"});{ "acknowledged" : true, "insertedId" : ObjectId("5e960099ed011c280a0905cd") } > db.demo602.insertOne({id:1, Name:"Sam"});{ "acknowledged" : true, "insertedId" : ObjectId("5e9600a1ed011c280a0905ce") }Display all documents from a collection with the help of find() method −> db.demo602.find();This will produce the following ... Read More
496 Views
Let us create a collection with documents −> db.demo601.insertOne( ... { ... id:1, ... userDetails: ... { ... userName:"John", ... userMailId:"John@gmail.com" ... } ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5e95ff5ced011c280a0905c7") } > > db.demo601.insertOne( { id:2, userDetails: { userName:"Carol", userMailId:"Carol@gmail.com" } } );{ "acknowledged" : true, "insertedId" : ObjectId("5e95ff71ed011c280a0905c8") }Display all documents from a collection with the help of find() method ... Read More
431 Views
For this, use userAdminAnyDatabase since it gives all permission like admin. Following is the syntax −use admin db.createUser( { user: "yourUserName", pwd: "yourPassword", roles: [ { role: "yourRoleName", db: "yourDatabaseName" } ] } )Let us implement the above syntax to create a user role. Following is the query to create a user with role "userAdminAnyDatabase" −> use admin switched to db admin > db.createUser( ... { ... user: "David Miller", ... pwd: "123456", ... roles: [ { role: "userAdminAnyDatabase", db: "admin" } ] ... } ... )This will produce the following output −Successfully added user: { "user" : "David Miller", "roles" : [ { "role" : "userAdminAnyDatabase", "db" : "admin" } ] }
404 Views
To update, use update() and following is the syntax to create and use a sample custom variable −var anyVariableName=yourValue; db.yourCollectionName.update({filter}, {$set:{yourFieldName:yourVariableName}});Let us create a collection with documents −> db.demo600.insertOne({id:1, Name:"Robert"});{ "acknowledged" : true, "insertedId" : ObjectId("5e94a063f5f1e70e134e2699") } > db.demo600.insertOne({id:2, Name:"Mike"});{ "acknowledged" : true, "insertedId" : ObjectId("5e94a06bf5f1e70e134e269a") } > db.demo600.insertOne({id:3, Name:"Sam"});{ "acknowledged" : true, "insertedId" : ObjectId("5e94a072f5f1e70e134e269b") }Display all documents from a collection with the help of find() method −> db.demo600.find();This will produce the following output −{ "_id" : ObjectId("5e94a063f5f1e70e134e2699"), "id" : 1, "Name" : "Robert" } { "_id" : ObjectId("5e94a06bf5f1e70e134e269a"), "id" : 2, "Name" : "Mike" } ... Read More
300 Views
To subtract values from document field values, use $subtract in MongoDB aggregate(). Let us create a collection with documents −> db.demo599.insertOne({"TotalPrice":250, "DiscountPrice":35});{ "acknowledged" : true, "insertedId" : ObjectId("5e948192f5f1e70e134e2696") } > db.demo599.insertOne({"TotalPrice":400, "DiscountPrice":10});{ "acknowledged" : true, "insertedId" : ObjectId("5e948199f5f1e70e134e2697") } > db.demo599.insertOne({"TotalPrice":1550, "DiscountPrice":50});{ "acknowledged" : true, "insertedId" : ObjectId("5e9481a0f5f1e70e134e2698") }Display all documents from a collection with the help of find() method −> db.demo599.find();This will produce the following output −{ "_id" : ObjectId("5e948192f5f1e70e134e2696"), "TotalPrice" : 250, "DiscountPrice" : 35 } { "_id" : ObjectId("5e948199f5f1e70e134e2697"), "TotalPrice" : 400, "DiscountPrice" : 10 } { "_id" : ObjectId("5e9481a0f5f1e70e134e2698"), "TotalPrice" : 1550, "DiscountPrice" ... Read More
335 Views
For this, use $avg along with $group and aggregate(). Let us create a collection with documents −> db.demo598.insertOne( ... { ... Information:'Student', ... id:100, ... details:[ ... {Name:'Chris', Marks:75}, ... {Name:'Bob', Marks:55} ... ] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5e947fccf5f1e70e134e2694") } > db.demo598.insertOne( ... { ... Information:'Student', ... id:101, ... details:[ ... {Name:'Chris', Marks:75}, ... ... Read More
759 Views
To find which document contains a specific string, use $regex along with find(). Let us create a collection with documents −> db.demo597.insertOne({"Name":"John Doe"});{ "acknowledged" : true, "insertedId" : ObjectId("5e947ae3f5f1e70e134e2690") } > db.demo597.insertOne({"Name":"John Smith"});{ "acknowledged" : true, "insertedId" : ObjectId("5e947ae8f5f1e70e134e2691") } > db.demo597.insertOne({"Name":"Chris Brown"});{ "acknowledged" : true, "insertedId" : ObjectId("5e947aeff5f1e70e134e2692") } > db.demo597.insertOne({"Name":"Adam Smith"});{ "acknowledged" : true, "insertedId" : ObjectId("5e947afff5f1e70e134e2693") }Display all documents from a collection with the help of find() method −> db.demo597.find();This will produce the following output −{ "_id" : ObjectId("5e947ae3f5f1e70e134e2690"), "Name" : "John Doe" } { "_id" : ObjectId("5e947ae8f5f1e70e134e2691"), "Name" : "John Smith" } ... Read More