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JComboBoxA JComboBox can extend JComponent class and it is a combination of a text field and a drop-down list from which the user can choose a value.If the text field portion of the control is editable, the user can enter a value in the field or edit a value retrieved from the drop-down list.By default, the user not allowed to edit the data in the text field portion of the JComboBox. If we want to allow the user to edit the text field, call setEditable(true) method.A JComboBox can generate an ActionListener, ChangeListener or ItemListener when the user actions on a combo box.A ... Read More
For the purpose of comparison, we can use number values as an argument in STRCMP() function. They are given as arguments without quotes. Following example will demonstrate it.Examplemysql> Select STRCMP(10, 10)As 'Equal Numbers', STRCMP(11, 10)AS '2nd Smaller', STRCMP(10, 11)AS '1st Smaller', STRCMP(10, NULL)As '2nd NULL', STRCMP(NULL, 10)AS '1st NULL', STRCMP(NULL, NULL)AS 'Both NULL'; +---------------+-------------+-------------+----------+----------+-----------+ | Equal Numbers | 2nd Smaller | 1st Smaller | 2nd NULL | 1st NULL | Both NULL | +---------------+-------------+-------------+----------+----------+-----------+ | 0 | 1 | -1 | NULL | ... Read More
Suppose we have the following table named ‘stock_item’ in which the column quantity is having duplicate values i.e. for item name ‘Notebooks’ and ‘Pencil’, the column ‘Quantity’ is having duplicate values ‘40’ as shown in the table.mysql> Select * from stock_item; +------------+----------+ | item_name |quantity | +------------+----------+ | Calculator | 89 | | Notebooks | 40 | | Pencil | 40 | | Pens | 32 | | Shirts | 29 | | Shoes | ... Read More
MySQL SPACE() function is used to add white spaces between two strings. The argument passed in SPACE() function is an integer which specifies how many white spaces we want to add.SyntaxSPACE(N)Here, N is an integer specifies the number of white spaces we want to add.Examplemysql> Select 'My Name is', Space(5), 'Ram'; +------------+----------+-----+ | My Name is | Space(5) | Ram | +------------+----------+-----+ | My Name is | | Ram | +------------+----------+-----+ 1 row in set (0.00 sec)In the example above, SPACE() function adds 5 white spaces between the strings.
In this case, SPACE() function would add white spaces depending upon the condition given in WHERE clause. The following example from student table will demonstrate it.Examplemysql> Select Id,Name,Space(5) from student WHERE Name='Harshit'; +------+---------+----------+ | Id | Name | Space(5) | +------+---------+----------+ | 15 | Harshit | | +------+---------+----------+ 1 row in set (0.00 sec)
The program uses a JLabel to hold a count label, a JTextField component to hold the number count, JButton component to create add, remove and reset buttons. When we click the add button, the count in the JTextField will get incremented by '1' and by clicking the remove button the count will be decremented by '1'. If we click the Reset button, it will reset the count to '0'.Exampleimport java.awt.*; import java.awt.event.*; import javax.swing.*; public class CounterTest extends JFrame implements ActionListener { private JLabel label; private JTextField text; private JButton addBtn, removeBtn, resetBtn; private int count; public CounterTest() { setTitle("Counter Test"); ... Read More
With the help of MySQL REPEAT() function, we can replicate a string for a specified number of times.SyntaxREPEAT(Str, No.)Here Str is the string which is to be replicated for a specified number of times.No. is the numerical value which indicates that how many times the string would be repeated.Examplemysql> Select REPEAT('#*',5); +----------------+ | REPEAT('#*',5) | +----------------+ | #*#*#*#*#* | +----------------+ 1 row in set (0.00 sec)
JTabbedPaneA JTabbedPane is a component can extend JComponent class and it can provide easy access to more than one panel.Each tab is associated with a single component that can be displayed when the tab is selected.A JTabbedPane can generate a ChangeListener interface when a tab is selected.The important methods of JTabbedPane are add(), addTab(), fireStateChanged(), createChangeListener(), setSelectedIndex(), getTabCount() and etc.Exampleimport java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.event.*; public class JTabbedPaneTest extends JFrame implements ActionListener { JTabbedPane tabbedPane; int ntabs = 0; public JTabbedPaneTest() { getContentPane().setLayout(new BorderLayout()); tabbedPane = new JTabbedPane(); ... Read More
A JDialog is a subclass of Dialog class and it does not hold minimize and maximize buttons at the top right corner of the window. We can create two types of JDialog boxes.in JavaModal DialogNon-Modal DialogModal JDialogIn Java, When a modal dialog window is active, all the user inputs are directed to it and the other parts of the application are inaccessible until this model dialog is closed.Non-Modal JDialogIn Java, When a non-modal dialog window is active, the other parts of the application are still accessible as normal and inputs can be directed to them, while this non-modal dialog window doesn't need to be ... Read More
MySQL has function name REVERSE() with the help of which we can reverse the string. But suppose if we want to reverse the string connected by dash then by using REVERSE() function will not give appropriate result as shown in the following example:mysql> Select REVERSE('AB-CD-EF'); +---------------------+ | REVERSE('AB-CD-EF') | +---------------------+ | FE-DC-BA | +---------------------+ 1 row in set (0.00 sec)The appropriate result would be ‘EF-CD-AB’ and for getting such output we can use SUBSTRING_INDEX() function along with Instr() function. It is demonstrated as follows:mysql> Select CONCAT(SUBSTRING_INDEX('AB-CD-EF', '-', -1), '-', substr('AB-CD-EF', instr('AB-CD-EF', "-")+1, instr('AB-CD-EF', "-")), LEFT('AB-CD-EF', ... Read More