Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>I tested your code and while I didn't get the exact same error, there's a couple of weird things:</p> <p>First, you are calling both <code>jMyTable.addColumn(...)</code> and <code>model.addColumn(...)</code>. Which is a mistake. You only need to call the model's addColumn. Adding also a column with the JTable method will create inconsistencies, because the TableModel and the TableColumnModel are not synchronized.</p> <p>Your code to add a new column into the model, and the calculation of the maximums is wrong. <code>i</code> should move through rows, and <code>j</code> should move through columns, and then check if we should do the <code>MAX[i] = ndata[i][j];</code> assignment. And while passing <code>new Object[0]</code> doesn't appear to cause any issues (because that constructor with a null value is valid) it doesn't make any sense.</p> <p>It should be something like this:</p> <pre><code>private void jFindmaximumActionPerformed(java.awt.event.ActionEvent evt) { DefaultTableModel model = (DefaultTableModel)jMYtable.getModel(); String headerLabel = "Maximum"; Object[] MAX = new Object[ndata.length]; for(int i = 0; i &lt; ndata.length; i++){ MAX[i] = ndata[i][0]; for(int j = 0 ; j &lt; ndata[0].length; j ++){ if(ndata[i][j] &gt; MAX[i]){ MAX[i] = ndata[i][j]; } } } model.addColumn(headerLabel, MAX); } </code></pre> <p>On a side note, if you ever were to implement your own TableModel, extending AbstractTableModel, when the memory structure (created and handled by yourself) that contains the table data changes, you have to update the table with the new values or new column/rows changes using an assortment of methods in the <code>AbstractTableModel</code> class to notify the JTable: <code>fireTableDataChanged()</code>, <code>fireRowsInserted()</code>, <code>fireTableStructureChanged()</code>...</p> <p><strong>UPDATE:</strong></p> <p>Here's a simple test code that adds columns to a JTable.</p> <pre><code>import java.awt.BorderLayout; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JTable; import javax.swing.SwingUtilities; import javax.swing.table.DefaultTableModel; public class SimpleColumnAdderFrame { private DefaultTableModel _model; public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { public void run() { new SimpleColumnAdderFrame().initUI(); } }); } public void initUI() { JFrame frame = new JFrame(); Object[][] data = { {1,2,3}, {10,20,30} }; String[] columnNames = {"Column 1", "Column 2", "Column 3"}; _model = new DefaultTableModel(data, columnNames); JTable table = new JTable(_model); JButton addColumnButton = new JButton("Add column"); addColumnButton.addActionListener(new ActionListener(){ public void actionPerformed(ActionEvent e) { int columns = _model.getColumnCount(); int rows = _model.getRowCount(); Object[] columnData = new Object[rows]; for (int i = 0; i &lt; rows; ++i) { columnData[i] = (int) ((columns + 1)*(Math.pow(10, i))); // &lt;- Unnecessarily complicated cell value } _model.addColumn("New Column " + (columns + 1), columnData); } }); JButton addRowButton = new JButton("Add row"); addRowButton.addActionListener(new ActionListener(){ public void actionPerformed(ActionEvent e) { int columns = _model.getColumnCount(); int rows = _model.getRowCount(); Object[] rowData = new Object[columns]; for (int i = 0; i &lt; columns; ++i) { rowData[i] = (int) ((i+1)*(Math.pow(10, rows))); // &lt;- Unnecessarily complicated cell value } _model.addRow(rowData); } }); JPanel buttonPanel = new JPanel(new GridLayout(1,2,2,2)); buttonPanel.add(addColumnButton); buttonPanel.add(addRowButton); frame.add(new JScrollPane(table), BorderLayout.CENTER); frame.add(buttonPanel, BorderLayout.PAGE_END); frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); frame.pack(); frame.setVisible(true); } } </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POAdd column to JTable that has some rows before adding
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USDSquare
    1. USDSquare
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COthanks dear DSquare for you help. I change my function and follow yours but my problem still remain. It really questionable... may be Netbeans IDE need to be more than these to do such thing...
      singulars
      1. PO
      1. USMorteza
    2. COAdding the column shouldn't be that hard. You can do a simple frame with a table and a button and it works well. The problem must be somewhere else.
      singulars
      1. PO
      1. USDSquare
    3. COSee my update above.
      singulars
      1. PO
      1. USDSquare
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload