Problem deleting rows using JDBC

Question

Hi,
I have a problem with the following code listed below. I am attempting to delete a user's details from a SQLServer db based on the user selected from a combobox. The code given below is just a section and relates to a JButton I have on the application that performs the delete command.
public void deleteButton_actionPerformed(ActionEvent e) {
try{
String opName = (String)userNameBox.getSelectedItem();
String deleteQuery = "select * from Operator where OperatorName = " + "'"+opName+"'";
//Load Database Driver Class
Class.forName(JDBC_DRIVER);
//Establish a connection to the Database
connection = DriverManager.getConnection(DATABASE_URL);
//Create Select statement for returning all usernames to the combobox
statement2 = connection.createStatement(java.sql.ResultSet.TYPE_SCROLL_SENSITIVE, java.sql.ResultSet.CONCUR_READ_ONLY);
//dQuery.setString(1,opName);
resultSet = statement2.executeQuery(deleteQuery);
while (resultSet.next()){
resultSet.deleteRow();
catch(Exception exception){
exception.printStackTrace();}
To explain the code, to begin with a String holds the value of the selected field of the combobox i have in my app. I have the SQL select statement the using this variable as the where clause.
The usual connection and statement objects are declared etc and then the query is executed. Within the While loop I then attempt to delete the row that the query has retrieved for me. However this results in the following error.
java.sql.SQLException: [Microsoft][ODBC SQL Server Driver]Invalid attribute/option identifier
Any help is much appreciated.
Thanks
Alan

Answer 1

Thanks for the reply. I understand your comment about
using the delete statement and it seems I am making
an obvious error. However I was using the select
statement to generate a resultSet object with which I
can delete elements from. Hence the reason for the
use of the select statement.This is brain dead, the classic newbie mistake. The database vendor has optimized their code more than you ever will in making those deletes, so use their code. Not only will they do it faster than you will, but you'll save yourself (n+1) network roundtrips (1 for the SELECT, 1 for each DELETE you issue). Better to learn SQL and use a WHERE clause to do it on the database side.
You have however solved the problem I had with
directly executing the delete statement as an SQL
String. I was using the following statement:
String deleteQuery = "select * from Operator where
OperatorName = " + "'"+opName+"'";
The wildcard character is not required and it was
this that gave me problems and made me look to using
a select query and deleting results from a
resultSet.Sounds like you need a SQL book. I recommend "SQL For Smarties".
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