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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to remove a record from an existing table in oracle database using JDBC API?
You can remove a particular record from a table in a database using the DELETE query.SyntaxDELETE FROM table_name WHERE [condition];To delete a record from a table using JDBC API you need to −Register the Driver: Register the driver class using the registerDriver() method of the DriverManager class. Pass the driver class name to it, as parameter.Establish a connection: Connect to the database using the getConnection() method of the DriverManager class. Passing URL (String), username (String), password (String) as parameters to it.Create Statement: Create a Statement object using the createStatement() method of the Connection interface.Execute the Query: Execute the query using the executeUpdate() method of the ...
Read MoreHow can we change the default font of the JTabbedPane tabs in Java?
To display the default font of the tabs, you need to use the Font class. Let’s say we created a JTabbedPane in Java −JTabbedPane tabbedPane = new JTabbedPane();Now, set the Font with font face, style and font size −Font font = new Font("Arial", Font.CENTER_BASELINE, 20); tabbedPane.setFont(font);The following is an example to change the default font of the JTabbedPane tabs −package my; import javax.swing.*; import java.awt.*; public class SwingDemo { public static void main(String args[]) { JFrame frame = new JFrame("Technologies"); JTabbedPane tabbedPane = new JTabbedPane(); JPanel panel1, panel2, panel3, panel4, ...
Read MoreCan we use {} while creating a MySQL table?
No, you need to use open and close parenthesis like this ( ) while creating a table. Use the below syntax −CREATE TABLE IF NOT EXISTS yourTableName ( yourColumnName1 dataType1, . . . . . N );Let us first create a table −mysql> CREATE TABLE IF NOT EXISTS DemoTable ( CustomerId int, CustomerName varchar(20), CustomerAge int , PRIMARY KEY(CustomerId) ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(1, 'Chris', 25); Query OK, 1 row ...
Read MoreHow to get the data type name from the java.sql.Type code using JDBC?
The java.sql.Types class represents the SQL datatype in integer format. The valueOf() method of the enumeration JDBCType accepts an integer value representing the java.sql.Type and, returns the JDBC type corresponding to the specified value.ExampleLet us create a table with name MyPlayers in MySQL database using CREATE statement as shown below −CREATE TABLE MyPlayers( ID INT, First_Name VARCHAR(255), Last_Name VARCHAR(255), Date_Of_Birth date, Place_Of_Birth VARCHAR(255), Country VARCHAR(255), PRIMARY KEY (ID) );Following JDBC program establishes connection with the MySQL database retrieves the contents of the MyPlayers table into a ResultSet object, obtains its metadata, obtains the column ...
Read MoreSum the values in a column in MySQL?
For this, use the aggregate function SUM(). Let us first create a table −mysql> create table DemoTable -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> € int -> ); Query OK, 0 rows affected (0.71 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(€) values(10); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(€) values(200); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable(€) values(190); Query OK, 1 row affected (0.14 sec)Display all records from the table using select statement −mysql> select *from ...
Read MoreWhat happen when we exceed valid range of built-in data types in C++?
Here we will see what will be the results, if we exceed the range of built-in datatypes in C++. So let us see some examples.First one is the character type data. Here we are using a loop from 0 to 300, so it should print from 0 to 300, then stop. But it will generate one infinite loop. The character type data holds from -128 to 127. So after increasing from 127, it will be -128 again. So it will never reach at the point 300.Example#include using namespace std; int main() { for (char x = 0; x ...
Read MoreHow to set the location of the Tabs in a JTabbedPane Container to the left in Java?
To set the location of the tabs in a JTabbedPane container, use the LEFT constant. Here, we will set the position to the left −JTabbedPane tabbedPane = new JTabbedPane(JTabbedPane.LEFT);The following is an example to set the location of the Tabs in a JTabbedPane Container to the left −Examplepackage my; import javax.swing.*; import java.awt.*; public class SwingDemo { public static void main(String args[]) { JFrame frame = new JFrame("Devices"); JTabbedPane tabbedPane = new JTabbedPane(JTabbedPane.LEFT); JTextArea text = new JTextArea(100, 100); JPanel panel1, panel2, panel3, panel4, panel5, panel6, panel7, ...
Read MoreMySQL query to convert a string like "1h 15 min" into 75 minutes?
You can use str_to_date() for this conversion. Let us first create a table −mysql> create table DemoTable ( stringDate varchar(100) ); Query OK, 0 rows affected (0.86 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('1h 15 min'); Query OK, 1 row affected (0.24 sec) mysql> insert into DemoTable values('2h 30 min'); Query OK, 1 row affected (0.21 sec)Display all records from the table using select statement −mysql> select *from DemoTable;Output+------------+ | stringDate | +------------+ | 1h 15 min | | 2h 30 min | +------------+ 2 rows in set ...
Read MoreMySQL query with OR & AND conditions
Let us first create a table −mysql> create table DemoTable -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Name varchar(20), -> Age int -> ); Query OK, 0 rows affected (0.63 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(Name, Age) values('John', 21); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable(Name, Age) values(Null, 20); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable(Name, Age) values('David', 23); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable(Name, Age) values('Carol', null); ...
Read MoreRule Of Three in C++
The Rule of three is a rule of thumb when using C++. This is kind of a good practice rule that says that If your class needs any ofa copy constructor, an assignment operator, or a destructor, defined explicitly, then it is likely to need all three of them.Why is this? It’s because, if your class requires any of the above, it is managing dynamically allocated resources and would likely be needing the other to successfully achieve that. For example, if you require an assignment operator, you would be creating copies of objects currently being copied by reference, hence allocating ...
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