Please help me get started with Databases...

Question

I've spent all day moving from one tutorial to the other trying to figure out how to use a Database with Java. I haven't found anything that explained things basic enough for me to understand, however, I did download and install MDAC 2.8 which was suggested in on one of the sites and I also have MS Access to work with for creating the database. Can somebody please explain what I need to do in order to access a database from my program in simple, easy to follow, steps?
Also I have a small question about .requestFocus();In my program I have a Radio button called Format1 and a text area called textArea. I set Format1 to be selected using the following code: Format1.setSelected(true); and I attempted to make the cursor start inside the text area with: textArea.requestFocus(); Currently, when I start the program, Format1 has the focus instead of textArea. How can I make the cursor start at the end of the text inside of textArea everytime I start my program?

Answer 1

Try this:
package be;
import java.sql.*;
import java.util.*;
public class DataConnection
    public static final String DEFAULT_DRIVER   = "sun.jdbc.odbc.JdbcOdbcDriver";
    public static final String DEFAULT_URL      = "jdbc:odbc:DRIVER={Microsoft Access Driver (*.mdb)};DBQ=e:\\Project\\Database.mdb";
    public static final String DEFAULT_USERNAME = "admin";
    public static final String DEFAULT_PASSWORD = "";
    /** Database connection */
    private Connection connection;
     * Driver for the DataConnection
     * @param command line arguments
     * <ol start='0'>
     * <li>SQL query string</li>
     * <li>JDBC driver class</li>
     * <li>database URL</li>
     * <li>username</li>
     * <li>password</li>
     * </ol>
    public static void main(String [] args)
        DataConnection db = null;
        try
            if (args.length > 0)
                String sql      = args[0];
                String driver   = ((args.length > 1) ? args[1] : DEFAULT_DRIVER);
                String url      = ((args.length > 2) ? args[2] : DEFAULT_URL);
                String username = ((args.length > 3) ? args[3] : DEFAULT_USERNAME);
                String password = ((args.length > 4) ? args[4] : DEFAULT_PASSWORD);
                db = new DataConnection(driver, url, username, password);
                List result = db.query(sql);
                System.out.println(result);
            else
                System.out.println("Usage: db.DataConnection <sql> <driver> <url> <username> <password>");
        catch (SQLException e)
            System.err.println("SQL error: " + e.getErrorCode());
            System.err.println("SQL state: " + e.getSQLState());
            e.printStackTrace(System.err);
        catch (Exception e)
            e.printStackTrace(System.err);
        finally
            if (db != null)
                db.close();
            db = null;
     * Create a DataConnection
     * @throws SQLException if the database connection fails
     * @throws ClassNotFoundException if the driver class can't be loaded
    public DataConnection() throws SQLException,ClassNotFoundException
        this(DEFAULT_DRIVER, DEFAULT_URL, DEFAULT_USERNAME, DEFAULT_PASSWORD);
     * Create a DataConnection
     * @throws SQLException if the database connection fails
     * @throws ClassNotFoundException if the driver class can't be loaded
    public DataConnection(final String driver,
                          final String url,
                          final String username,
                          final String password)
        throws SQLException,ClassNotFoundException
        Class.forName(driver);
        this.connection = DriverManager.getConnection(url, username, password);
     * Clean up the connection
    public void close()
        try
            this.connection.close();
        catch (Exception e)
            ; // do nothing; you've done your best
     * Execute an SQL query
     * @param SQL query to execute
     * @returns list of row values
     * @throws SQLException if the query fails
    public List query(final String sql) throws SQLException
        Statement statement     = this.connection.createStatement();
        ResultSet rs            = statement.executeQuery(sql);
        ResultSetMetaData meta  = rs.getMetaData();
        int numColumns          = meta.getColumnCount();
        List rows               = new ArrayList();
        while (rs.next())
            Map thisRow = new LinkedHashMap();
            for (int i = 1; i <= numColumns; ++i)
                String columnName   = meta.getColumnName(i);
                Object value        = rs.getObject(columnName);
                thisRow.put(columnName, value);
            rows.add(thisRow);
        rs.close();
        statement.close();
        return rows;
}Solve one problem at a time. Get the database going, then worry about how you'll present it to the users. - MOD