我在本教程的最后一页:http: //www.homeandlearn.co.uk/java/delete_a_record_from_a_database.html这是关于删除 Derby 数据库中的记录。我的删除按钮代码如下:
private void btnDeleteRecordActionPerformed(java.awt.event.ActionEvent evt) {
try{
String host = "jdbc:derby://localhost:1527/Employees";
String uName = "bjorn";
String uPass= "";
con = DriverManager.getConnection( host, uName, uPass );
PreparedStatement pstmt = con.prepareStatement("SELECT * FROM App.Workers",ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
con.setAutoCommit(false);
rs = pstmt.executeQuery();
//count++;
if (rs.absolute(count)) {
rs.absolute(count);
//rs.next();
rs.deleteRow( );
pstmt.close( );
rs.close( );
}
}
catch (SQLException err) {
System.out.println(err.getMessage() );
}
}
我有两个问题:为什么不起作用rs.deleteRow( );
?
当我在方法中包含以下代码时,它给了我错误:
Invalid operation at current cursor position.
stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
String sql = "SELECT * FROM App.Workers";
rs = stmt.executeQuery(sql);
int id_col = rs.getInt("ID");
String id = Integer.toString(id_col);
String first2 = rs.getString("First_Name");
String last2 = rs.getString("Last_Name");
String job2 = rs.getString("Job_Title");
textID.setText(id);
textFirstName.setText(first2);
textLastName.setText(last2);
textJobTitle.setText(job2);
stmt.close( );
此代码应该重新加载文本字段中的所有数据。什么是不给出此异常的工作代码?