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To get number of records, use count() in MongoDB. Let us create a collection with documents −> db.demo697.insertOne({Name:"Chris", Age:21}); { "acknowledged" : true, "insertedId" : ObjectId("5ea6d7d1551299a9f98c9395") } > db.demo697.insertOne({Name:"Bob", Age:23}); { "acknowledged" : true, "insertedId" : ObjectId("5ea6d7d8551299a9f98c9396") } > db.demo697.insertOne({Name:"David", Age:24}); { "acknowledged" : true, "insertedId" : ObjectId("5ea6d7dd551299a9f98c9397") }Display all documents from a collection with the help of find() method −> db.demo697.find();This will produce the following output −{ "_id" : ObjectId("5ea6d7d1551299a9f98c9395"), "Name" : "Chris", "Age" : 21 } { "_id" : ObjectId("5ea6d7d8551299a9f98c9396"), "Name" : "Bob", "Age" : 23 } { "_id" : ObjectId("5ea6d7dd551299a9f98c9397"), "Name" ... Read More
To pull an element, use $pull along with $(positional) operator. Let us create a collection with documents −> db.demo679.insertOne( ... { ... id:1, ... "details": [ ... { ... CountryName:"US", ... "information": [ ... ... { "Name": "Chris", "FirstName": "Name=Chris" }, ... ... {"Name": "Bob", "FirstName": "Name=Bob" } ... ] ... }, ... ... Read More
For this, use find() along with //i. Let us create a collection with documents −> db.demo696.insertOne({Message:"/Good/"}); { "acknowledged" : true, "insertedId" : ObjectId("5ea6d664551299a9f98c9391") } > db.demo696.insertOne({Message:"(good)"}); { "acknowledged" : true, "insertedId" : ObjectId("5ea6d67a551299a9f98c9392") } > db.demo696.insertOne({Message:"/Bye/"}); { "acknowledged" : true, "insertedId" : ObjectId("5ea6d68b551299a9f98c9393") } > db.demo696.insertOne({Message:"(GOOD)"}); { "acknowledged" : true, "insertedId" : ObjectId("5ea6d693551299a9f98c9394") }Display all documents from a collection with the help of find() method −> db.demo696.find();This will produce the following output −{ "_id" : ObjectId("5ea6d664551299a9f98c9391"), "Message" : "/Good/" } { "_id" : ObjectId("5ea6d67a551299a9f98c9392"), "Message" : "(good)" } { "_id" : ObjectId("5ea6d68b551299a9f98c9393"), ... Read More
For this, use ensureIndex(). Let us create a collection with documents −> db.demo678.ensureIndex({id:1,"details.userId":1}); { "createdCollectionAutomatically" : true, "numIndexesBefore" : 1, "numIndexesAfter" : 2, "ok" : 1 } > db.demo678.insertOne( ... { ... id:101, ... ... "details" : [ ... { ... "userId" : "1001", ... "userName":"Chris" ... }, ... { ... "userId" : "1002", ... "userName":"David" ... } ... ], ... "otherDetails" : [ ... { ... CountryName:"US", ... EmailId:["Chris@gmail.com","David@gmail.com"] ... } ... ] ... } ... ); { "acknowledged" : true, "insertedId" : ObjectId("5ea4276904263e90dac943fc") }Display all documents from a collection with the help of find() method −> db.demo678.find();This will produce the following output −{ "_id" : ObjectId("5ea4276904263e90dac943fc"), "id" : 101, "details" : [ { "userId" : "1001", "userName" : "Chris" }, { "userId" : "1002", "userName" : "David" } ], "otherDetails" : [ { "CountryName" : "US", "EmailId" : [ "Chris@gmail.com", "David@gmail.com" ] } ] }
To match all in MongoDB, 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.demo695.insertOne({"ListOfValues":[100, 200, 500, 800]}); { "acknowledged" : true, "insertedId" : ObjectId("5ea6d4c4551299a9f98c938f") } > db.demo695.insertOne({"ListOfValues":[1000, 200, 4000]}); { "acknowledged" : true, "insertedId" : ObjectId("5ea6d4cf551299a9f98c9390") }Display all documents from a collection with the help of find() method −> db.demo695.find();This will produce the following output −{ "_id" : ObjectId("5ea6d4c4551299a9f98c938f"), "ListOfValues" : [ 100, 200, 500, 800 ] } { "_id" : ObjectId("5ea6d4cf551299a9f98c9390"), "ListOfValues" ... Read More
Let us see an example and create a collection with documents −> db.demo694.insertOne( ... { ... "details" : ... [ ... { ... "Name" : "Chris", ... Age:21 ... }, ... { ... "Name" : "David", ... Age:22 ... } ... ] ... } ... ); { "acknowledged" ... Read More
For this, use $slice and set thecount of values to be ignored and displayed. Let us create a collection with documents −> db.demo693.insertOne({Values:[10, 746, 736, 283, 7363, 424, 3535]}); { "acknowledged" : true, "insertedId" : ObjectId("5ea58a04ece4e5779399c07b") } > db.demo693.insertOne({Values:[100, 200, 300, 100, 500, 700, 900, 30000, 40003, 45999]}); { "acknowledged" : true, "insertedId" : ObjectId("5ea58a1eece4e5779399c07c") }Display all documents from a collection with the help of find() method −> db.demo693.find();This will produce the following output −{ "_id" : ObjectId("5ea58a04ece4e5779399c07b"), "Values" : [ 10, 746, 736, 283, 7363, 424, 3535 ] } { "_id" : ObjectId("5ea58a1eece4e5779399c07c"), "Values" : ... Read More
To find documents with specific FirstName and LastName, use $and along with $in. Implement this in MongoDB find(). Let us create a collection with documents −> db.demo692.insertOne({FirstName:"Chris", "LastName":"Brown"}); { "acknowledged" : true, "insertedId" : ObjectId("5ea585dca7e81adc6a0b396a") } > db.demo692.insertOne({FirstName:"John", "LastName":"Brown"}); { "acknowledged" : true, "insertedId" : ObjectId("5ea585e2a7e81adc6a0b396b") } > db.demo692.insertOne({FirstName:"John", "LastName":"Smith"}); { "acknowledged" : true, "insertedId" : ObjectId("5ea585e7a7e81adc6a0b396c") } > db.demo692.insertOne({FirstName:"John", "LastName":"Doe"}); { "acknowledged" : true, "insertedId" : ObjectId("5ea585efa7e81adc6a0b396d") } > db.demo692.insertOne({FirstName:"Adam", "LastName":"Smith"}); { "acknowledged" : true, "insertedId" : ObjectId("5ea585faa7e81adc6a0b396e") }Display all documents from a collection with the help of find() ... Read More
The novalidate attribute in HTML is used to signify that the form won’t get validated on submit. It is a Boolean attribute and useful if you want the user to save the progress of form filing. If the form validation is disabled, the user can easily save the form and continue & submit the form later. While continuing, the user does not have to first validate all the entries.ExampleYou can try to run the following code to learn how to use novalidate attribute in HTML. In the following example, if you will add text in the field, then it won’t show ... Read More
To rename a collection in MongoDB, use renameCollection(). Let us create a collection with documents −> db.demo690.insertOne({_id:101, Name:"Sam"}); { "acknowledged" : true, "insertedId" : 101 } > db.demo690.insertOne({_id:102, Name:"Mike"}); { "acknowledged" : true, "insertedId" : 102 } > db.demo690.insertOne({_id:103, Name:"John"}); { "acknowledged" : true, "insertedId" : 103 }Display all documents from a collection with the help of find() method −> db.demo690.find();This will produce the following output −{ "_id" : 101, "Name" : "Sam" } { "_id" : 102, "Name" : "Mike" } { "_id" : 103, "Name" : "John" }Following is the query to rename collection −> db.demo690.renameCollection("demo691"); { "ok" ... Read More