Updating TableModel if changing data on DataBase(MySQL)

Hi everyone!. I have a problem with the table (JTable). I created a table model:

Code :

---

import java.util.ArrayList;
 
import javax.swing.table.AbstractTableModel;
 
@SuppressWarnings("serial")
public class MyListTableModel extends AbstractTableModel {
 
	private ArrayList<String>				columnNames	= new ArrayList<String>();
	private ArrayList<ArrayList<Object>>	data		= new ArrayList<ArrayList<Object>>();
 
	public MyListTableModel(ArrayList<ArrayList<Object>> data, ArrayList<String> columnNames) {
		this.columnNames = columnNames;
		this.data = data;
		fireTableDataChanged();
	}
 
	@SuppressWarnings({ "unchecked", "rawtypes" })
	public Class getColumnClass(int c) {
		return getValueAt(0, c).getClass();
	}
 
	public int getColumnCount() {
		return columnNames.size();
	}
 
	public String getColumnName(int col) {
		return columnNames.get(col);
	}
 
	public int getRowCount() {
		synchronized (data) {
			return data.size();
		}
	}
 
	public Object getValueAt(int row, int col) {
		synchronized (data) {
			return data.get(row).get(col);
		}
	}
 
	public boolean isCellEditable(int row, int col) {
		return false;
	}
 
	public void setValueAt(String obj, int row, int col) {
		synchronized (data) {
			data.get(row).set(col, obj);
			fireTableDataChanged();
		}
	}
}

---

and develop JTable from this model:

Code :

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	private class CalcTableUI extends JScrollPane {
		CalcTableUI() throws Exception {
			calcTbl = new JTable(new MyListTableModel(createArrayListData(SQLQueriesBank.getCalcPosting), createArrayListColumns(SQLQueries.getPostTitle)));
			setViewportView(calcTbl);
			revalidate();
		}
	}

---

Code :

---

public static ArrayList<ArrayList<Object>> createArrayListData(String sqlQuery) throws Exception {
		Connection conn = getConnectToMySQLDB();
		ArrayList<ArrayList<Object>> dataArLst = new ArrayList<ArrayList<Object>>();
		try {
			PreparedStatement st = conn.prepareStatement(sqlQuery);
			ResultSet rs = st.executeQuery();
			ResultSetMetaData md = rs.getMetaData();
			int columnCount = md.getColumnCount();
			while (rs.next()) {
				ArrayList<Object> rowArr = new ArrayList<Object>(columnCount);
				for (int i = 1; i <= columnCount; i++) {
					rowArr.add(rs.getString(i));
				}
				rowArr.trimToSize();
				dataArLst.add(rowArr);
			}
			dataArLst.trimToSize();
		} catch (Exception e) {
			JOptionPane.showMessageDialog(new JDialog(), e);
		} finally {
			if (conn != null)
				conn.close();
		}
		return dataArLst;
	}

---

Code :

---

public static ArrayList<String> createArrayListColumns(String sqlQuery) throws Exception {
		Connection conn = getConnectToMySQLDB();
		ArrayList<String> columnsArr = new ArrayList<String>();
		try {
			PreparedStatement st = conn.prepareStatement(sqlQuery);
			ResultSet rs = st.executeQuery();
			while (rs.next()) {
				columnsArr.add(rs.getString(1));
			}
			columnsArr.trimToSize();
		} catch (Exception e) {
			JOptionPane.showMessageDialog(new JDialog(), e);
		} finally {
			if (conn != null)
				conn.close();
		}
		return columnsArr;
	}

---

but when i changing DB tables its not effect to the my CalcTableUI, when i rerun my app, its shows changing, why. where i wrong and/or what is missing ?

Are you saying you're updating the data stored in the model but the JTable isn't showing the change?

You shouldn't expect the table to change, as when you load the data into the table you have 2 copies of the data. How does one know to change when the other changes? This problem is a lot harder to solve than one might think, one solution would be to build a notification system (which in its simplest form would require an inner tier to keep track and notify all clients of a datachange, and all changes go through this tier). This is not trivial