Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
For this, use initializeOrderedBulkOp(). It initializes and returns a new Bulk() operations builder for a collection. The builder constructs an ordered list of write operations that MongoDB executes in bulk.Let us create a collection with documents −>db.demo550.insertOne({"Name":"Chris", "details":[{"Marks":49, Result:"fail"}, {"Marks":58, Result:"fail"}]}); { "acknowledged" : true, "insertedId" : ObjectId("5e8e35bd9e5f92834d7f05e4") }Display all documents from a collection with the help of find() method −> db.demo550.find();This will produce the following output −{ "_id" : ObjectId("5e8e35bd9e5f92834d7f05e4"), "Name" : "Chris", "details" : [ { "Marks" : 49, "Result" : "fail" }, { "Marks" : 58, "Result" : "fail" } ] }Following is the query ... Read More
To find a specific amount of records, use LIMIT() in MongoDB. The method accepts one number type argument, which is the number of documents that you want to be displayed.Let us create a collection with documents −> db.demo549.insertOne({"Name":"Chris"});{ "acknowledged" : true, "insertedId" : ObjectId("5e8e32889e5f92834d7f05df") } > db.demo549.insertOne({"Name":"David"});{ "acknowledged" : true, "insertedId" : ObjectId("5e8e328c9e5f92834d7f05e0") } > db.demo549.insertOne({"Name":"Bob"});{ "acknowledged" : true, "insertedId" : ObjectId("5e8e328f9e5f92834d7f05e1") } > db.demo549.insertOne({"Name":"John"});{ "acknowledged" : true, "insertedId" : ObjectId("5e8e32929e5f92834d7f05e2") }Display all documents from a collection with the help of find() method −> db.demo549.find();This will produce the following output −{ "_id" : ObjectId("5e8e32889e5f92834d7f05df"), "Name" : ... Read More
To add a multi-line text input, use the HTML tag. You can set the size of a text area using the cols and rows attributes. It is used within a form, to allow users to input text over multiple rows.Here are the attributes of tag −AttributeValueDescriptionautofocusautofocusSpecifies that on page load the text area should automatically get focus.ColsnumberSpecifies the width of the textarea based on the number of visible character widthsDisableddisabledSpecifies the width of the textarea based on the number of visible character widths.formform_idSpecifies one or more forms.maxlengthnumberSpecifies the maximum number of characters in textarea.NametextAssigns a name to the ... Read More
The mongo shell provides various methods like ISODate() to return the date, either as a string or as a Date object. ISODate() constructor returns a Date object using the ISODate() wrapper.Let us create a collection with documents −> db.demo548.insertOne({"dueDate":new ISODate("2020-04-09 12:12:40")});{ "acknowledged" : true, "insertedId" : ObjectId("5e8e30499e5f92834d7f05de") }Display all documents from a collection with the help of find() method −> db.demo548.find();This will produce the following output −{ "_id" : ObjectId("5e8e30499e5f92834d7f05de"), "dueDate" : ISODate("2020-04- 09T12:12:40Z") }Following is the query to display, month, day, week, year, etc. from ISODate −> db.demo548.aggregate( [ { $project: { Year: { $year: "$dueDate" }, ... Read More
For update, simply use update(). Use the $push operator to append a specified value and the dot notation to reach the sub collection and update inside update().Let us create a collection with documents −> db.demo547.insertOne( ... { ... Name : "Chris", ... Test : ... { ... "FirstTest" : ... { ... Scores: [56, 29, 76] ... }, ... "SecondTest" : ... { ... Scores: [98, 91, 78] ... } ... ... Read More
The $redact restricts the contents of the documents based on information stored in the documents themselves. You can use $cond along with $redact in aggregate. Let us create a collection with documents −> db.demo546.insertOne({"Value1":10, "Value2":20});{ "acknowledged" : true, "insertedId" : ObjectId("5e8e263f9e5f92834d7f05d7") } > db.demo546.insertOne({"Value1":40, "Value2":30, Value3:50});{ "acknowledged" : true, "insertedId" : ObjectId("5e8e26549e5f92834d7f05d8") } > db.demo546.insertOne({"Value1":100, "Value2":200, Value3:null});{ "acknowledged" : true, "insertedId" : ObjectId("5e8e26619e5f92834d7f05d9") } > db.demo546.insertOne({"Value1":400, "Value2":1000, Value3:null});{ "acknowledged" : true, "insertedId" : ObjectId("5e8e26e09e5f92834d7f05da") } > db.demo546.insertOne({"Value1":400, "Value2":200, Value3:null});{ "acknowledged" : true, "insertedId" : ObjectId("5e8e26f59e5f92834d7f05db") } > db.demo546.insertOne({"Value1":400, "Value2":1000, Value3:60});{ "acknowledged" : true, "insertedId" ... Read More
The $match filters the documents to pass only the documents that match the specified condition to the next pipeline stage.The $project passes along the documents with the requested fields to the next stage in the pipeline.Let us see an example and create a collection with documents −> db.demo545.insert({Name:"Chris", details:{SubjectScore1:56, SubjectScore2:56}}) WriteResult({ "nInserted" : 1 }) > db.demo545.insert({Name:"David", details:{SubjectScore1:78, SubjectScore2:78}}) WriteResult({ "nInserted" : 1 })Display all documents from a collection with the help of find() method −> db.demo545.find();This will produce the following output −{ "_id" : ObjectId("5e8e246e9e5f92834d7f05d5"), "Name" : "Chris", "details" : { "SubjectScore1" : 56, "SubjectScore2" : 56 } } ... Read More
The mongo shell provides the NumberLong() wrapper to handle 64-bit integers. Following is the syntax using custom variable and print using toString() −var anyVariableName=NumberLong("yourLongNumber"); yourVariableName.toString();To understand the above concept, let us implement the above syntax −> var number=NumberLong("231231231231121231"); > number.toString();This will produce the following output −NumberLong("231231231231121231")The second example is as follows to display NumberLong −> var anotherNumber=NumberLong("765765765765567576"); > anotherNumber.toString();This will produce the following output −NumberLong("765765765765567576")
To aggregate, use aggregate() in MongoDB. It calculates aggregate values for the data in a collection.Let us create a collection with documents −> db.demo544.insertOne({"DueTime":new ISODate("2020-01-10 12:10:20"), Amount:100});{ "acknowledged" : true, "insertedId" : ObjectId("5e8e1f029e5f92834d7f05ce") } > db.demo544.insertOne({"DueTime":new ISODate("2020-01-12 12:00:00"), Amount:500});{ "acknowledged" : true, "insertedId" : ObjectId("5e8e1f089e5f92834d7f05cf") } > db.demo544.insertOne({"DueTime":new ISODate("2020-01-12 12:10:20"), Amount:900});{ "acknowledged" : true, "insertedId" : ObjectId("5e8e1f109e5f92834d7f05d0") }Display all documents from a collection with the help of find() method −> db.demo544.find();This will produce the following output −{ "_id" : ObjectId("5e8e1f029e5f92834d7f05ce"), "DueTime" : ISODate("2020-01-10T12:10:20Z"), "Amount" : 100 } { "_id" : ObjectId("5e8e1f089e5f92834d7f05cf"), "DueTime" : ISODate("2020-01-12T12:00:00Z"), ... Read More
To find a document that matches the same array elements, use find() and within that, use $all. The $all operator selects the documents where the value of a field is an array that contains all the specified elements.Let us create a collection with documents −> db.demo543.insertOne({id:101, subject:["MySQL", "Java" ,"C", "Python"]});{ "acknowledged" : true, "insertedId" : ObjectId("5e8e1b2f9e5f92834d7f05c9") } > db.demo543.insertOne({id:102, subject:["MySQL", "MongoDB" ,"SQL Server"]});{ "acknowledged" : true, "insertedId" : ObjectId("5e8e1b2f9e5f92834d7f05ca") }Display all documents from a collection with the help of find() method −> db.demo543.find();This will produce the following output −{ "_id" : ObjectId("5e8e1b2f9e5f92834d7f05c9"), "id" : 101, "subject" ... Read More