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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to find middle element in a linked list in android?
This example demonstrate about How to finding middle element in a linked list 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 find the middle element.Step 3 − Add the following code to src/MainActivity.javapackage com.example.myapplication; import android.os.Build; import android.os.Bundle; import android.support.annotation.RequiresApi; import android.support.v7.app.AppCompatActivity; import android.widget.TextView; import java.util.LinkedList; public class MainActivity extends AppCompatActivity { @RequiresApi(api ...
Read MoreHow to efficiently perform “distinct” with multiple keys in MongoDB?
You can perform distinct with multiple keys with the help of an aggregate framework.To understand the concept, let us create a collection with the document. The query to create a collection with a document is as follows −> db.distinctWithMultipleKeysDemo.insertOne({"StudentName":"Mike", "StudentAge":22, "StudentMathMarks":56}); { "acknowledged" : true, "insertedId" : ObjectId("5c7f74488d10a061296a3c53") } > db.distinctWithMultipleKeysDemo.insertOne({"StudentName":"Mike", "StudentAge":22, "StudentMathMarks":56}); { "acknowledged" : true, "insertedId" : ObjectId("5c7f744b8d10a061296a3c54") } > db.distinctWithMultipleKeysDemo.insertOne({"StudentName":"Bob", "StudentAge":23, "StudentMathMarks":45}); { "acknowledged" : true, "insertedId" : ObjectId("5c7f74598d10a061296a3c55") } > db.distinctWithMultipleKeysDemo.insertOne({"StudentName":"Bob", "StudentAge":23, "StudentMathMarks":45}); { "acknowledged" : true, "insertedId" : ObjectId("5c7f745e8d10a061296a3c56") } > db.distinctWithMultipleKeysDemo.insertOne({"StudentName":"Carol", "StudentAge":27, "StudentMathMarks":54}); { "acknowledged" ...
Read MoreHandling optional/empty data in MongoDB?
In order to handle empty data, you can use $ne operator. Let us create a collection with documents. Following is the query>db.handlingAndEmptyDataDemo.insertOne({"StudentName":"John", "StudentCountryName":""}); { "acknowledged" : true, "insertedId" : ObjectId("5c9cbd5ca629b87623db1b12") } >db.handlingAndEmptyDataDemo.insertOne({"StudentName":"John", "StudentCountryName":null}); { "acknowledged" : true, "insertedId" : ObjectId("5c9cbd6ba629b87623db1b13") } > db.handlingAndEmptyDataDemo.insertOne({"StudentName":"John"}); { "acknowledged" : true, "insertedId" : ObjectId("5c9cbd71a629b87623db1b14") }Following is the query to display all documents from a collection with the help of find() method> db.handlingAndEmptyDataDemo.find().pretty();This will produce the following output{ "_id" : ObjectId("5c9cbd5ca629b87623db1b12"), "StudentName" : "John", "StudentCountryName" : "" } { "_id" : ObjectId("5c9cbd6ba629b87623db1b13"), "StudentName" : ...
Read MoreCounting number of positive and negative votes in MySQL?
To count number of positive and negative votes, you can use CASE statement along with aggregate function SUM().Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Vote int ); Query OK, 0 rows affected (1.70 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(Vote) values(-10); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable(Vote) values(100); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable(Vote) values(45); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable(Vote) values(-6); Query OK, 1 row ...
Read MoreComparing dates in MySQL ignoring time portion of a DateTime field?
To compare dates in MySQL except time portion of a datetime field, you can use DATE() function. The syntax is as follows −select *from yourTableName where date(yourColumName) = yourDate;To understand the above concept, let us create a table. The query to create a table is as follows −mysql> create table ComparingDate −> ( −> Name varchar(100), −> Login datetime −> ); Query OK, 0 rows affected (0.50 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> insert into ComparingDate values('John', '2014-04-06 22:50:45'); Query OK, 1 row affected ...
Read Moreftp_chmod() function in PHP
The ftp_chmod() function set permissions on a remote file via FTP.Syntaxftp_chmod(con, mode, my_file);Parameterscon − The FTP connectionmode − The new permissions.It consists of four numbers −The first number is always zeroThe second number specifies permissions for the OWNERThe third number specifies permissions for the OWNER's USER GROUPThe fourth number specifies permissions for EVERYBODY ELSEPossible values (to set multiple permissions, add up the following numbers) −1 = execute permissions2 = write permissions4 = read permissionsmy_file − The File nameReturnThe ftp_chmod() function returns new file permissions on success or FALSE on error.ExampleThe following is an example to set file permission by changing ...
Read Moreftp_close() function in PHP
The ftp_close() function closes an FTP connection.Syntaxftp_close(con);Parameterscon − The connection to close.ReturnThe ftp_close() function returns TRUE on success or FALSE on failureExampleThe following is an example that login to a connection, works in it to change the directory and then connection is closed −
Read MoreThe equivalent of SQL Server function SCOPE_IDENTITY() in MySQL?
The equivalent of SQL Server function SCOPE_IDENTITY() is equal to LAST_INSERT_ID() in MySQL. The syntax is as follows:SELECT LAST_INSERT_ID().This returns the id of last inserted record.Here, I am going to create a table with primary key column. The following is the demo of last_insert_id().First, let us create two tables. The query to create the first table table is as follows:mysql> create table TestOnLastInsertIdDemo -> ( -> StudentId int NOT NULL AUTO_INCREMENT, -> PRIMARY KEY(StudentId) -> ); Query OK, 0 rows affected (0.95 sec)Now creating the second table. The query is as follows:mysql> create table TestOnLastInsertIdDemo2 ...
Read MoreCreate date from day, month, year fields in MySQL?
You can use in-built function STR_TO_DATE() from MySQL. The syntax is as follows −SELECT STR_TO_DATE(CONCAT(yourYearColumName, '-', LPAD(yourMonthColumName, 2, '00'), '-', LPAD(yourDayColumName, 2, '00')), '%Y-%m-%d') as anyVariableName from yourTableName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table DateCreateDemo −> ( −> `Day` varchar(2), −> `Month` varchar(2), −> `Year` varchar(4) −> ); Query OK, 0 rows affected (1.68 sec)Insert values for all fields using insert command. The query is as follows −mysql> insert into DateCreateDemo values('15', '12', '2018'); Query OK, 1 row affected (0.09 ...
Read MoreDo we need to be certified in order to teach quantitative aptitude for SAT (in India)?
There is no certification nor one required to teach Quantitative aptitude for SAT. The faculty should have the required qualification and experience though.
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