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Articles by Ankith Reddy
Page 60 of 73
Can I get the first item in a Cursor object in MongoDB?
Yes, you can get the first item in a cursor object using findOne() method. Following is the syntaxdb.yourCollectionName.findOne();However, the following syntax is used if you want a single document in a cursor objectdb.yourCollectionName.findOne({yourCondition});We will first create a collection. Following is the query to create a collection with documents> db.getFirstItemDemo.insertOne({"CustomerName":"Chris", "CustomerAge":28}); { "acknowledged" : true, "insertedId" : ObjectId("5c989059330fd0aa0d2fe4c1") } > db.getFirstItemDemo.insertOne({"CustomerName":"Larry", "CustomerAge":26}); { "acknowledged" : true, "insertedId" : ObjectId("5c989063330fd0aa0d2fe4c2") } > db.getFirstItemDemo.insertOne({"CustomerName":"Robert", "CustomerAge":29}); { "acknowledged" : true, "insertedId" : ObjectId("5c98906d330fd0aa0d2fe4c3") } > db.getFirstItemDemo.insertOne({"CustomerName":"David", "CustomerAge":39}); { "acknowledged" : true, "insertedId" : ObjectId("5c989081330fd0aa0d2fe4c4") }Following is ...
Read MoreHow to increment all the rows of a particular column by 1 in a single MySQL query (ID column +1)?
To increment all the rows of a particular ID column by 1, you need to use UPDATE command and update the table. The syntax of the query is as follows. We have also used ORDER BY hereUPDATE yourTableName SET yourIdColumnName=yourIdColumnName+1 ORDER BY yourIdColumnName DESC;To understand the above syntax, let us create a table. The query to create a table is as followsmysql> create table IdColumnadd1Demo - > ( - > Id int NOT NULL AUTO_INCREMENT PRIMARY KEY - > ); Query OK, 0 rows affected (0.58 sec)Insert some records in the ...
Read MoreGetting a distinct aggregation of an array field across indexes
To get a distinct aggregation of an array field across indexes, let us take an example and create a collection with some documents.Following is the query to create a collection with documents> db.distinctAggregation.insertOne({"UserName":"Larry", "UserPost":["Hi", "Hello"]}); { "acknowledged" : true, "insertedId" : ObjectId("5c98aefb330fd0aa0d2fe4c6") } > db.distinctAggregation.insertOne({"UserName":"Chris", "UserPost":["Hi", "Good Morning"]}); { "acknowledged" : true, "insertedId" : ObjectId("5c98af0a330fd0aa0d2fe4c7") } > db.distinctAggregation.insertOne({"UserName":"Robert", "UserPost":["Awesome"]}); { "acknowledged" : true, "insertedId" : ObjectId("5c98af1e330fd0aa0d2fe4c8") }Following is the query to display all documents from a collection with the help of find() method> db.distinctAggregation.find().pretty();This will produce the following output{ "_id" : ObjectId("5c98aefb330fd0aa0d2fe4c6"), ...
Read MoreHow to set two variables in a stored procedure with a single MySQL select statement?
For this, let us first create a new table in MySQLmysql> create table useProcedure - > ( - > Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, - > FirstName varchar(20), - > LastName varchar(20) - > ); Query OK, 0 rows affected (0.65 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into useProcedure(FirstName, LastName) values('Adam', 'Smith'); Query OK, 1 row affected (0.27 sec)The following is your stored procedure to set two variables in a stored procedure with single select ...
Read MoreHow to specify exact order with WHERE `id` IN (…) in MySql?
To specify exact order with where id IN, you need to use find_in_set() function.The syntax is as followsSELECT *FROM yourTableName WHERE yourColumnName IN (yourValue1, yourValue2, yourValue3, ....N) ORDER BY FIND_IN_SET(yourColumnName , ‘yourValue1, yourValue2, yourValue3, ....N’');Let us first create a tablemysql> create table FindInSetDemo - > ( - > Id int, - > Name varchar(20), - > Age int - > ); Query OK, 0 rows affected (0.54 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into FindInSetDemo values(10, 'John', 23); Query OK, 1 row affected (0.20 sec) mysql> insert ...
Read MoreReturn True if a document exists in MongoDB?
Let us first create a collection. Following is the query to create a collection with documents> db.documentExistsOrNotDemo.insertOne({"UserId":101, "UserName":"John"}); { "acknowledged" : true, "insertedId" : ObjectId("5c9932bd330fd0aa0d2fe4cf") } > db.documentExistsOrNotDemo.insertOne({"UserId":102, "UserName":"Chris"}); { "acknowledged" : true, "insertedId" : ObjectId("5c9932c6330fd0aa0d2fe4d0") } > db.documentExistsOrNotDemo.insertOne({"UserId":102, "UserName":"Robert"}); { "acknowledged" : true, "insertedId" : ObjectId("5c9932ce330fd0aa0d2fe4d1") }Following is the query to display all the documents from a collection with the help of find() method> db.documentExistsOrNotDemo.find().pretty();This will produce the following output{ "_id" : ObjectId("5c9932bd330fd0aa0d2fe4cf"), "UserId" : 101, "UserName" : "John" } { "_id" : ObjectId("5c9932c6330fd0aa0d2fe4d0"), "UserId" : 102, ...
Read MoreIn C++ What are the differences between a pointer variable and a reference variable?
ReferencesWhen a variable is declared as reference, it becomes an alternative name for an existing variable.SyntaxType &newname = existing name;InitializatioType &pointer; pointer = variable name;PointersPointers are used to store the address of variable.SyntaxType *pointer;InitializationType *pointer; pointer = variable name;The main differences between references and pointers are -References are used to refer an existing variable in another name whereas pointers are used to store address of variable.References cannot have a null value assigned but pointer can.A reference variable can be referenced by pass by value whereas a pointer can be referenced but pass by reference.A reference must be initialized on declaration ...
Read MoreFind all the non-distinct values of a field in MongoDB?
Use aggregate() method to get all the non-distinct values of a field. Let us first create a collection with documents> db.findAllNonDistinctDemo.insertOne({"UserName":"John", "UserAge":28}); { "acknowledged" : true, "insertedId" : ObjectId("5c995078863d6ffd454bb647") } > db.findAllNonDistinctDemo.insertOne({"UserName":"Larry", "UserAge":21}); { "acknowledged" : true, "insertedId" : ObjectId("5c995081863d6ffd454bb648") } > db.findAllNonDistinctDemo.insertOne({"UserName":"Larry", "UserAge":23}); { "acknowledged" : true, "insertedId" : ObjectId("5c995089863d6ffd454bb649") } > db.findAllNonDistinctDemo.insertOne({"UserName":"David", "UserAge":22}); { "acknowledged" : true, "insertedId" : ObjectId("5c995093863d6ffd454bb64a") } > db.findAllNonDistinctDemo.insertOne({"UserName":"John", "UserAge":26}); { "acknowledged" : true, "insertedId" : ObjectId("5c99509d863d6ffd454bb64b") } > db.findAllNonDistinctDemo.insertOne({"UserName":"Robert", "UserAge":24}); { "acknowledged" : true, "insertedId" : ObjectId("5c9950a7863d6ffd454bb64c") } > db.findAllNonDistinctDemo.insertOne({"UserName":"Robert", "UserAge":25}); ...
Read MoreGet the last record from a table in MySQL database with Java?
To get data from MySQL database, you need to use executeQuery() method from java. First create a table in the MySQL database. Here, we will create the following table in the ‘sample’ databasemysql> create table javaGetDataDemo - > ( - > Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, - > FirstName varchar(10), - > LastName varchar(10) - > ); Query OK, 0 rows affected (0.80 sec)Now you can insert some records in the table using insert command.The query is as followsmysql> insert into javaGetDataDemo(FirstName, LastName) values('John', 'Smith'); Query OK, 1 row affected (0.19 sec) mysql> insert into javaGetDataDemo(FirstName, LastName) values('Carol', ...
Read MoreHow to get default phone MmsUserAgent in android?
This example demonstrate about How to get default phone MmsUserAgent in android.Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. In the above code, we have taken a text view to show phone MmsUserAgent.Step 3 − Add the following code to java/MainActivity.xmlpackage com.example.myapplication; import android.Manifest; import android.content.Context; import android.content.pm.PackageManager; import android.os.Build; import android.os.Bundle; import android.support.annotation.NonNull; import android.support.annotation.RequiresApi; import android.support.v4.app.ActivityCompat; import android.support.v7.app.AppCompatActivity; import android.telephony.TelephonyManager; import android.widget.TextView; import static android.Manifest.permission.READ_PHONE_NUMBERS; import static android.Manifest.permission.READ_PHONE_STATE; ...
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