Question

Note – this follows my question here: JDBC: Does the connection break if i lose reference to the Connection object?

Now i have a created a class so i can deal with JDBC easily for the rest of my code –

public class Functions {
    private String DB_SERVER = "";
    private String DB_NAME = "test";
    private String DB_USERNAME = "root";
    private String DB_PASSWORD = "password";

    public  Connection con;
    public  PreparedStatement ps;
    public  ResultSet rs;
    public  ResultSetMetaData rsmd;

    public void connect()
            throws java.io.FileNotFoundException, java.io.IOException,
            SQLException, Exception    {
        String[] dbParms = Parameters.load();

        DB_SERVER = dbParms[0];
        DB_NAME = dbParms[1];
        DB_USERNAME = dbParms[2];
        DB_PASSWORD = dbParms[3];

        // Connect.
        Class.forName("com.mysql.jdbc.Driver").newInstance();
        con = DriverManager.getConnection("jdbc:mysql://"
                + DB_SERVER + "/"
                + DB_NAME, DB_USERNAME, DB_PASSWORD);
    }

    public void disconnect() throws SQLException  {
        // Close.
        con.close();
    }
}

As seen Parameters.load() refreshes the connection parameters from a file every-time, so that any changes to the same may be applied on the next immediate connection.

An example of this class in action –

public static void add(String NAME)
        throws java.io.FileNotFoundException, java.io.IOException, SQLException, Exception    {
    Functions dbf = new Functions();
    dbf.connect();

    String query = "INSERT INTO " + TABLE_NAME + "(" +
            "NAME" +
            ") VALUES(?)";
    PreparedStatement ps = dbf.con.prepareStatement(query);
    ps.setString(1, NAME);
    ps.executeUpdate();

    dbf.disconnect();
}

Now here is the problem – for adding a record to the table above, the add() method will open a connection, add the record – and then call disconnect() .

What if i want to get the ID of the inserted record after i call add() -like this :

Department.add("new dept");
int ID = getlastID();

Isn’t it possible that another add() was called between those two statements?

Answer 1

It’s possible .. you might want to consider refactoring your code.

Baby steps, retrieve and store the id in a variable inside your add method before closing the connection, change the signature and return the id.