Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
Database Articles
Page 442 of 546
Retrieve only the queried element in an object array in MongoDB collection?
You can use projection operator $elemMatch to filter in queried element in an object array in MongoDB collection. To retrieve only the queried element in an object array in MongoDB, let us first create a collection with documents object array.The query is as follows:> db.objectArray.insert({"Persons":[ {"PersonName":"Adam", "PersonSalary":25000}, {"PersonName":"Larry", "PersonSalary":27000 }]}); WriteResult({ "nInserted" : 1 }) > db.objectArray.insert({"Persons":[ {"PersonName":"David", "PersonSalary":32000}, {"PersonName":"Carol", "PersonSalary":77000 }]}); WriteResult({ "nInserted" : 1 })Now you can display all the documents with the help of find(). The query is as follows:> db.objectArray.find().pretty();The following is the output:{ "_id" : ObjectId("5c6bfadc68174aae23f5ef53"), "Persons" ...
Read MoreFind objects between two dates in MongoDB?
Use operator $gte and $lt to find objects between two dates in MongoDB. To understand these operators, let us create a collection.Creating a collection here:>db.order.insert({"OrderId":1, "OrderAddrees":"US", "OrderDateTime":ISODate("2019-02-19")}; WriteResult({ "nInserted" : 1 }) >db.order.insert({"OrderId":2, "OrderAddrees":"UK", "OrderDateTime":ISODate("2019-02-26")}; WriteResult({ "nInserted" : 1 })Display all documents from the collection with the help of find() method. The query is as follows:> db.order.find().pretty();The following is the output:{ "_id" : ObjectId("5c6c072068174aae23f5ef57"), "OrderId" : 1, "OrderAddrees" : "US", "OrderDateTime" : ISODate("2019-02-19T00:00:00Z") } { "_id" : ObjectId("5c6c073568174aae23f5ef58"), "OrderId" : 2, "OrderAddrees" : "UK", "OrderDateTime" : ISODate("2019-02-26T00:00:00Z") }Here is the query ...
Read MoreGet names of all keys in the MongoDB collection?
The syntax to get names of all keys in the collection is as follows:var yourVariableName1=db.yourCollectionName.findOne(); for(var yourVariableName 2 in yourVariableName1) { print(yourVariableName); }To understand the above syntax, let us create a collection with documents. The collection name we are creating is “studentGetKeysDemo”.The following is the query to create documents:>db.studentGetKeysDemo.insert({"StudentId":1, "StudentName":"Larry", "StudentAge":23, "StudentAddress":"US", ... "StudentHobby":["Cricket", "Football", "ReadingNovel"], "StudentMathMarks":89, "StudentDOB":ISODate('1998-04-06')});The following is the output:WriteResult({ "nInserted" : 1 })Display all documents from a collection with the help of find() method. The query is as follows:> db.studentGetKeysDemo.find().pretty();The following is the output:{ "_id" : ObjectId("5c6c12dd68174aae23f5ef5f"), "StudentId" : 1, "StudentName" : ...
Read MoreGet Random record from MongoDB?
To get a random record from MongoDB, you can use aggregate function. The syntax is as follows:db.yourCollectionName.aggregate([{$sample:{size:1}}]);To understand the above syntax, let us create a collection with some documents. The query to create collection is as follows:>db.employeeInformation.insert({"EmployeeId":1, "EmployeeName":"Maxwell", "EmployeeAge":26}); WriteResult({ "nInserted" : 1 }) >db.employeeInformation.insert({"EmployeeId":2, "EmployeeName":"David", "EmployeeAge":25}); WriteResult({ "nInserted" : 1 }) >db.employeeInformation.insert({"EmployeeId":3, "EmployeeName":"Carol", "EmployeeAge":24}); WriteResult({ "nInserted" : 1 }) >db.employeeInformation.insert({"EmployeeId":4, "EmployeeName":"Bob", "EmployeeAge":28}); WriteResult({ "nInserted" : 1 }) >db.employeeInformation.insert({"EmployeeId":5, "EmployeeName":"Sam", "EmployeeAge":27); WriteResult({ "nInserted" : 1 })Now you can display all documents from a collection with the help of find() method. The query is as follows:> db.employeeInformation.find().pretty();The following is the output:{ ...
Read MoreHow to filter array in subdocument with MongoDB?
You can use aggregate and unwind the array list before applying match. To understand the above concept, let us create a collection with documents. The query to create a collection with document is as follows:> db.filterArray.insertOne( { "L": [{ "N":1 }, { "N":2 } , { "N":3 }, { "N":4 }, { "N":5 } ]});The following is visible after running the above query:{ "acknowledged" : true, "insertedId" : ObjectId("5c6d63f2734e98fc0a434aeb") }Display document from a collection with the help of find() method. The query is as follows:> db.filterArray.find().pretty();The following is the output:{ "_id" : ObjectId("5c6d63f2734e98fc0a434aeb"), "L" : [ ...
Read MoreQuery for documents where array size is greater than 1 in MongoDB?
You can use length to query for documents where array size is greater than 1:db.yourCollectionName.find({$where:"this.yourArrayDocumentName.length > 1"}).pretty();To understand the above syntax, let us create a collection with some documents. The query is as follows to create a collection with documents:>db.arrayLengthGreaterThanOne.insertOne({"StudentName":"Larry", "StudentTechnicalSubje ct":["Java", "C", "C++"]}); { "acknowledged" : true, "insertedId" : ObjectId("5c6d6c4c0c3d5054b766a76a") } >db.arrayLengthGreaterThanOne.insertOne({"StudentName":"Maxwell", "StudentTechnicalSu bject":["MongoDB"]}); { "acknowledged" : true, "insertedId" : ObjectId("5c6d6c660c3d5054b766a76b") } >db.arrayLengthGreaterThanOne.insertOne({"StudentName":"Maxwell", "StudentTechnicalSu bject":["MySQL", "SQL Server", "PL/SQL"]}); { "acknowledged" : true, "insertedId" : ObjectId("5c6d6c800c3d5054b766a76c") }Display all documents from a collection with the help of find() method. The query is as follows:> db.arrayLengthGreaterThanOne.find().pretty();The ...
Read MoreFind document with array that contains a specific value in MongoDB
You can use find() method to find document with array that contains a specific value. The syntax is as follows:db.yourCollectionName.find({"yourArrayFieldName":"yourValue"}, .......N).pretty();To understand the above syntax, let us create a collection with documents. The query to create a collection with documents is as follows:>db.findSpecificValue.insertOne({"StudentId":1, "StudentName":"Larry", "FavouriteSubject":["C", "C++", "Java"]}); { "acknowledged" : true, "insertedId" : ObjectId("5c6e8996140577d89182b8d0") } >db.findSpecificValue.insertOne({"StudentId":2, "StudentName":"Larry", "FavouriteSubject":["MongoDB", "MySQL", "SQL Server"]}); { "acknowledged" : true, "insertedId" : ObjectId("5c6e89b1140577d89182b8d1") }Display all documents from a collection with the help of find() method. The query is as follows:> db.findSpecificValue.find().pretty();The following is the output:{ "_id" : ObjectId("5c6e8996140577d89182b8d0"), "StudentId" ...
Read MoreUpdate field in exact element array in MongoDB?
You can update the in exact element array in MongoDB with the help of below statement. The syntax is as follows:{"yourArrayDocumentName.$.yourNestedArrayDocument.yourPosition":"yourValue"}});To understand the above syntax, let us create a collection with some documents. The query to create a collection with document is as follows:> db.updateExactField.insertOne({"ActorId":1, "ActorDetails":[{"ActorName":"Johnny Depp", "MovieList": ["The Tourist", "Public Enemy"]}, ... {"ActorName":"Chris Evans", "MovieList":["Captain America", "Avengers"]}]}); { "acknowledged" : true, "insertedId" : ObjectId("5c6d7f63f2db199c1278e7f1") }Now you can display documents from a collection with the help of find() method. The query is as follows:> db.updateExactField.find().pretty();The following is the output:{ "_id" : ObjectId("5c6d7f63f2db199c1278e7f1"), "ActorId" : 1, ...
Read MoreHow to remove array element in MongoDB?
To remove array element in MongoDB, you can use $pull and $in operator. The syntax is as follows:db.yourCollectionName.update({}, {$pull:{yourFirstArrayName:{$in:["yourValue"]}, yourSecondArrayName:"yourValue"}}, {multi:true} );To understand the above syntax, let us create a collection with document. The query to create a collection with document is as follows:>db.removeArrayElement.insertOne({"StudentName":"Larry", "StudentCoreSubject":["MongoD B", "MySQL", "SQL Server", "Java"], "StudentFavouriteTeacher":["John", "Marry", "Carol"]}); { "acknowledged" : true, "insertedId" : ObjectId("5c6ec9c46fd07954a4890688") }Display all documents from a collection with the help of find() method. The query is as follows:> db.removeArrayElement.find().pretty();The following is the output:{ "_id" : ObjectId("5c6ec9c46fd07954a4890688"), "StudentName" : "Larry", "StudentCoreSubject" : [ ...
Read MoreBest way to store date/time in MongoDB?
There are two different ways by which you can store date/time in MongoDB. In the first approach, you can use Date objects like JavaScript. The Date object is the best way to store date/time in MongoDB. The syntax is as follows:new Date();In the second approach, you can use ISODate(). The syntax is as follows:new ISODate();To understand the above syntax, let us create a collection with documents following the first approach. The query to create a collection with document is as follows:The first approach:> db.ProductsInformation.insertOne({"ProductId":"Product-1", "ProductDeliveryDateTime":new Date()}); { "acknowledged" : true, "insertedId" : ObjectId("5c6ec6786fd07954a4890686") }The second approach:> db.ProductsInformation.insertOne({"ProductId":"Product-2", "ProductDeliveryDateTime":new ...
Read More