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Articles on Trending Technologies
Technical articles with clear explanations and examples
Check if value exists in a comma separated list in MySQL?
To check if value exists in a comma separated list, you can use FIND_IN_SET() function.The syntax is as followsSELECT *FROM yourTablename WHERE FIND_IN_SET(‘yourValue’, yourColumnName) > 0;Let us first create a table. The query to create a table is as followsmysql> create table existInCommaSeparatedList - > ( - > Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, - > Name varchar(200) - > ); Query OK, 0 rows affected (0.68 sec)Now you can insert some records in the table using insert command.The query is as followsmysql> insert into existInCommaSeparatedList(Name) values('John, ...
Read MoreHow to use take() in android ArrayBlockingQueue?
Before getting into the example, we should know what arrayblockingqueue is, it travels FIFO manner and the first element going to live the longest period of time and last element of the queue going to live a short period of the time.This example demonstrates about How to use take() in android ArrayBlockingQueueStep 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 ...
Read MoreResolve Unknown database in JDBC error with Java-MySQL?
This type of error occurs if you select any database that does not exist in MySQL. Let us first display the error of unknown database in JDBC.The Java code is as follows. Here, we have set the database as ‘onlinebookstore’, which does not exist:import java.sql.Connection; import java.sql.DriverManager; public class UnknownDatabaseDemo { public static void main(String[] args) { String JdbcURL = "jdbc:mysql://localhost:3306/onlinebookstore?useSSL=false"; String Username = "root"; String password = "123456"; Connection con = null; try { con = DriverManager.getConnection(JdbcURL, Username, password); ...
Read MoreC++ Program to Implement Coppersmith Freivald's Algorithm
Freivalds' algorithm determines whether the matrices are equal for a chosen k value with a probability of failure less than 2^-k in O(kn^2).It is used to verify matrix multiplication.AlgorithmBegin Take matrix1(n*n), matrix2(n*n), matrix3(n*n) as input. // According to the algorithm we have to verify: // matrix1 × matrix2 = matrix3. 1) Choose vector a[n][1] randomly and uniformly in which component will be 0 or 1. 2) Compute matrix2 * a, matrix3 * a and then matrix1 * (matrix2 * a) for evaluating the expression, matrix1 * (matrix2 * a) - matrix3 * a. 3) ...
Read MoreHow to get server_id in MySQL?
To get the server_id, use the system defined variable @@server_id. You cannot use only a single @ as user defined variable for server_id.The syntax is as followsSELECT@@ server_idAs an alternate, you can use SHOW VARIABLES command.The syntax is as followsSHOW VARIABLES LIKE ‘server_id’;Case 1The query is as followsmysql> SELECT @@server_id as SERVER_ID;The following is the output+-----------+ | SERVER_ID | +-----------+ | 1 | +-----------+ 1 row in set (0.00 sec)Case 2The query is as followsmysql> show variables like 'server_id';The following is the output+---------------+-------+ | Variable_name | Value | +---------------+-------+ | server_id | ...
Read MoreHow to connect to Derby database using a JDBC program?
Apache Derby is a Relational Database Management System which is fully based on (written/implemented in) Java programming language. It is an open source database developed by Apache Software Foundation.Installing derby:Follow the steps given below to install derby:Visit the home page of Apache Derby home page https://db.apache.org/derby/. Click the Download tab.Select and click on the link of the latest version of Apache Derby.On clicking the selected link, you will be redirected to the Distributions page of apache derby. If you observe here, derby provides distributions namely, db-derby-bin, db-derbylib.zip, db-derby-lib-debug.zip, and db-derby-src.zip.Download the db-derby-bin folder. Copy its contents to a separate folder ...
Read MoreAndroid create shortcuts on the home screen
This example demonstrates about Uninstall APKs programmaticallyStep 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.Step 3 − Add the following code to src/MainActivity.javapackage com.example.myapplication; import android.app.Activity; import android.content.Intent; import android.content.SharedPreferences; import android.net.Uri; import android.os.Bundle; import android.support.v4.content.pm.ShortcutInfoCompat; import android.support.v4.content.pm.ShortcutManagerCompat; import android.support.v4.graphics.drawable.IconCompat; import android.view.View; import android.widget.TextView; import android.widget.Toast; public class MainActivity extends Activity { private static final String PREF_KEY_SHORTCUT_ADDED = "Sairam"; TextView ...
Read MoreDifference between count(*) and count(columnName) in MySQL?
The count(*) returns all rows whether column contains null value or not while count(columnName) returns the number of rows except null rows.Let us first create a table.Following is the querymysql> create table ifNotNullDemo -> ( -> Name varchar(20) -> ); Query OK, 0 rows affected (0.54 sec)Following is the query to insert some records in the table using insert command:mysql> insert into ifNotNullDemo values('Chris'); Query OK, 1 row affected (0.15 sec) mysql> insert into ifNotNullDemo values(''); Query OK, 1 row affected (0.13 sec) mysql> insert into ifNotNullDemo values('Robert'); Query OK, 1 row affected (0.24 sec) ...
Read MoreC++ Program to Implement Gauss Jordan Elimination
This is a C++ Program to Implement Gauss Jordan Elimination. It is used to analyze linear system of simultaneous equations. It is mainly focused on reducing the system of equations to a diagonal matrix form by row operations such that the solution is obtained directly.AlgorithmBegin n = size of the input matrix To find the elements of the diagonal matrix: Make nested for loops j = 0 to n and i = 0 to n The element in the first row and the first column is made 1 and then the ...
Read MoreHow to make embedded youtube videos look better on your website?
We can embed YouTube videos on our websites, however, the alignment might not be the liking of a lot of people. Some might want the window size to be slightly different, or the appearance to be otherwise. These are some additional adjustments that we can make to change the appearance:Step 1: After you get your desired video on your page, you have to make two precisely minor adjustments. The first task you should do is to adjust the height of the player to 24 pixels tall. So, now change 182 from the embed code to 24.Step 2: After the step 1 ...
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