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Articles on Trending Technologies
Technical articles with clear explanations and examples
Check a column for unique value in MySQL
You can use subquery for this. Let us first create a demo tablemysql> create table uniqueBothColumnValueSameDemo -> ( -> UserId int, -> UserValue int -> ); Query OK, 0 rows affected (0.64 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into uniqueBothColumnValueSameDemo values(10, 20); Query OK, 1 row affected (0.21 sec) mysql> insert into uniqueBothColumnValueSameDemo values(10, 20); Query OK, 1 row affected (0.09 sec) mysql> insert into uniqueBothColumnValueSameDemo values(20, 30); Query OK, 1 row affected (0.10 sec) mysql> insert into uniqueBothColumnValueSameDemo values(20, 40); Query OK, 1 row affected ...
Read MoreHow to set default date time as system date time in MySQL?
You can use CURRENT_TIMESTAMP to set system date time. Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, ClientFirstName varchar(20), ClientLastName varchar(20), ClientAge int ); Query OK, 0 rows affected (0.66 sec)Following is the query to set default datetime as system date time in MySQL −mysql> alter table DemoTable add column ClientProjectDeadline timestamp default current_timestamp; Query OK, 0 rows affected (0.46 sec) Records: 0 Duplicates: 0 Warnings: 0Let us check the description of table once again −mysql> desc DemoTable;This will produce the following output −+-----------------------+-------------+------+-----+-------------------+----------------+ | Field ...
Read More8085 Program to simulate a real-time clock
Now let us see a program of Intel 8085 Microprocessor. In this program we will see how to generate real time clock using 8085.Problem Statement:Write 8085 Assembly language program to simulate real-time clock.Discussion:In this program we are creating a real time clock using 8085MPU. Here we are generating 1s delay to update seconds. This clock is 24Hrs clock. We are initializing the clock from 00:00:00. To display the values into 7-segment display we have to use some Port ICs and correct configurations. In each 60 seconds the minute field is updated, and in each 60 minutes the hour field is ...
Read MoreHow to use singleton dialog in android?
Before getting into an example, we should know what singleton design pattern is. A singleton is a design pattern that restricts the instantiation of a class to only one instance. Notable uses include controlling concurrency and creating a central point of access for an application to access its data store.This example demonstrates How to use singleton dialog in androidStep 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 ...
Read MoreCreate Unit Tuple from another collection in Java
To create Unit Tuple from another collection, use the fromCollection() method.Let us first see what we need to work with JavaTuples. To work with the Unit class in JavaTuples, you need to import the following package −import org.javatuples.Unit;Note − Steps to download and run JavaTuples program. If you are using Eclipse IDE to run Unit Class in Java Tuples, then Right Click Project → Properties → Java Build Path → Add External Jars and upload the downloaded JavaTuples jar file.The following is an example −Exampleimport java.util.*; import org.javatuples.Unit; public class Demo { public static void main(String[] args) { ...
Read MoreHow to create IntSummaryStatistics from Collectors in Java?
Let us first create a List:List emp = Arrays.asList( new Employee("John", "Marketing", 5), new Employee("David", "Operations", 10));We have class Employee with name, department and rank of employees.Now, create summary for the rank like count, average, sum, etc:IntSummaryStatistics summary = emp .stream() .collect(Collectors.summarizingInt(p -> p.rank));The following is an example to create IntSummaryStatistics from Collectors in Java:Exampleimport java.util.Arrays; import java.util.IntSummaryStatistics; import java.util.List; import java.util.stream.Collectors; public class Demo { public static void main(String[] args) throws Exception { List emp = Arrays.asList(new Employee("John", "Marketing", 5), new Employee("David", "Operations", 10)); IntSummaryStatistics summary = emp .stream() .collect(Collectors.summarizingInt(p → ...
Read MoreDelete one row and reorder the others with the correct ID in MySQL?
To understand the concept, let us first create a table. The query to create a table is as followsmysql> create table ReorderSortDemo -> ( -> UserId int -> ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into ReorderSortDemo values(14); Query OK, 1 row affected (0.13 sec) mysql> insert into ReorderSortDemo values(4); Query OK, 1 row affected (0.10 sec) mysql> insert into ReorderSortDemo values(6); Query OK, 1 row affected (0.11 sec) mysql> insert into ReorderSortDemo values(3); Query ...
Read MoreHow to set/insert null values to in to a column of a row using JDBC program?
You can insert null values into a table in SQL in two ways:Directly inserting the value NULL into the desired column as:Insert into SampleTable values (NULL);Using ‘ ’ as nullInsert into SampleTable values (NULL);While inserting data into a table using prepared statement object you can set null values to a column using the setNull() method of the PreparedStatement interface.pstmt.setNull(parameterIndex, sqlType);ExampleAssume we have a table named cricketers_data in the database with the following contents:+------------+------------+---------------+----------------+-------------+ | First_Name | Last_Name | Date_Of_Birth | Place_Of_Birth | Country | +------------+------------+---------------+----------------+-------------+ | Shikhar | Dhawan | 1981-12-05 | ...
Read MoreHow to extract part of a URL in MySQL?
You need to use SUBSTRING_INDEX() function from MySQL to extract part of a URL. Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, URL text ); Query OK, 0 rows affected (0.53 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(URL) values('https:\www.example.com\homepage'); Query OK, 1 row affected (0.27 sec) mysql> insert into DemoTable(URL) values('https:\www.onlinetest.com\welcome\indexpage'); Query OK, 1 row affected (0.12 sec)Following is the query to display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output. Here, we can ...
Read MoreHow to change font size with HTML in Java Swing JEditorPane?
Use HTMLEditorKitt to change the font size with HTML. With that, use the JEditorPane setText() method to set HTML:HTMLEditorKit kit = new HTMLEditorKit(); editorPane.setEditorKit(kit); editorPane.setSize(size); editorPane.setOpaque(true); editorPane.setText(" This is a demo text with a different font!");The following is an example to change font size with HTML in Java Swing JEditorPane:Exampleimport java.awt.BorderLayout; import java.awt.Container; import java.awt.Dimension; import javax.swing.JEditorPane; import javax.swing.JFrame; import javax.swing.text.html.HTMLEditorKit; public class SwingDemo extends JFrame { public static void main(String[] args) { SwingDemo s = new SwingDemo(); s.setSize(600, 300); Container container = s.getContentPane(); s.demo(container, container.getSize()); ...
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