JAVA

Traversing To and Fro with SQL Server Based Java Applications using NetBeans IDE

This series introduces you to a step-by-step process for developing Java (or JFC) based applications with Microsoft SQL Server as the database, using NetBeans IDE. In this article (which is the last in this series), I shall introduce you to traversing through a set of rows more efficiently. This will be a bit different from any of the articles in this series.

Author Info:

By: Jagadish Chaterjee

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June 28, 2006

TABLE OF CONTENTS:

// TODO add your handling code here:
        try{
         if (rset.last()) {
                this.txtEmpno.setText(rset.getString(1));
                this.txtEname.setText(rset.getString(2));
                this.txtSal.setText(rset.getString(3));
                this.txtDeptno.setText(rset.getString(4));
            }
        }
        catch(Exception e) {
            this.lblMsg.setText("Error: Please view Stack
Trace");
            e.printStackTrace();
        }
    }
    private void btnFirstActionPerformed(java.awt.event.ActionEvent evt) {

// TODO add your handling code here:
        try{
         if (rset.first()) {
                this.txtEmpno.setText(rset.getString(1));
                this.txtEname.setText(rset.getString(2));
                this.txtSal.setText(rset.getString(3));
                this.txtDeptno.setText(rset.getString(4));
            }
        }
        catch(Exception e) {
            this.lblMsg.setText("Error: Please view Stack
Trace");
            e.printStackTrace();
        }
    }
    private void btnPreviousActionPerformed(java.awt.event.ActionEvent evt) {

// TODO add your handling code here:
       try{
         if (rset.previous()) {
                this.txtEmpno.setText(rset.getString(1));
                this.txtEname.setText(rset.getString(2));
                this.txtSal.setText(rset.getString(3));
                this.txtDeptno.setText(rset.getString(4));
            }
        }
        catch(Exception e) {
            this.lblMsg.setText("Error: Please view Stack
Trace");
            e.printStackTrace();
        }
    }
    private void btnNextActionPerformed
(java.awt.event.ActionEvent evt) {

// TODO add your handling code here:
        try{
         if (rset.next()) {
                this.txtEmpno.setText(rset.getString(1));
                this.txtEname.setText(rset.getString(2));
                this.txtSal.setText(rset.getString(3));
                this.txtDeptno.setText(rset.getString(4));
            }
        }
        catch(Exception e) {
            this.lblMsg.setText("Error: Please view Stack
Trace");
            e.printStackTrace();
        }

}

The above code is using methods such as previous, next, last and first. They can be used if and only if we declare the "Statement" object as follows:

sql_stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
ResultSet.CONCUR_READ_ONLY);

This is quite essential if you need to move freely in any direction. According to the above statement, I also declared the result set to be read-only. That means it cannot be modified by the user any more. Since our design is not for modifications, I used it. But you can't use it if you need the result set to be updatable.

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