Checking if a record exists

Hello : )

I've been having trouble writing this code that should be relatively simple. I'm wanting to check if a record exists, if it does then it is deleted, if not then a JOptionPane shows up. My experience in SQL is limited but I don't think this should require much SQL knowledge in the first place to execute. I've spent a deal of time on the internet looking for solutions, but I am never able to successfully implement them into my code. Is there a simple way to do this that I am overlooking? I'll post the code of the method below in case it helps.

Thanks in advance for your time and help!

public void remove() throws SQLException, ClassNotFoundException {
			
			try {
				Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); //load the driver
				Connection con = DriverManager.getConnection("jdbc:odbc:Nutrition"); //establish connection
				Statement sqlStatement = con.createStatement(); //create statement
				String queryString = ""; //query
				String name = t6.getText();
				String booleanString = "SELECT COUNT (foodName) FROM Nutrition Where foodName = '" +
					name + "'";
				
				sqlStatement.execute(booleanString);
				ResultSet resultSet = sqlStatement.getResultSet(); //result set for records
				boolean recordFound = resultSet.next();
		
				if (recordFound) {
			
				queryString = "DELETE FROM Nutrition WHERE foodName = '" + name + "'";
				sqlStatement.execute(queryString);
				JOptionPane.showMessageDialog(null, "Successful Removal");
	       	
				t1.setText("");
				t2.setText("");
				t3.setText("");
				t4.setText("");
				t5.setText("");
				t6.setText("");
	       	
				sqlStatement.close();
	       		con.close();
			} //ends if statement
				
				else {
					JOptionPane.showMessageDialog(null, "No food with that name exists" +
							"in the database");
				}
			}//ends try block
	
			catch (Exception ex) {
				JOptionPane.showMessageDialog(null, "Error:" + ex);
			}
		} //ends remove() method

The first query will always return exactly one record. (The value of COUNT(*) will be zero if the query didn't count any records, but there will still be one record containing that zero.)

But I don't see why you're trying to find out if a record exists. Just execute the delete statement and be done with it. (Although you should use the executeUpdate method instead; it returns a number which tells you how many records were deleted. Which might be zero.)

Like Paul said, if you are deleteing something from a database, there is no need to check if it already exists. If a record does not exist, then the command does nothing. Calling executeUpdate will return the number of rows that were modified by the call. Here is some psuedo code

You might also consider declaring your connection and statements outside the try statement so that you can close them in a finally block. Right now, if your code produced an exception, the connection would stay open.

You should be using a java.sql.PreparedStatement instead of a regular Statement. It offers protection against sql injection attacks. Look at the beginning of the javadoc for an example.