Wierd behavior from MySQL queries

Question

I have a really frustrating problem in my JSP app that only seems to be occuring sporadically... I have to deploy it on an NT machine that is available right now. I'm using Tomcat/MySQL. I've had it on a W2000 machine and it has worked fine. To complicate things, the NT that it is on does have a proxy server that it must go through...it doesn't seem to want to work during the day, but in the evenings (presumably less traffic?), it has yet to fail me.
The part of the app that won't update properly is responsible for letting people sign into an office cube daily, updating a seat table in the MYSQL database. It 1st checks to see if the person is assigned to another seat, and deletes that entry if they are. It then updates the seat table, replacing '0' (meaning no one's sitting here) with the person's emp_id. Here's the code for these 2 methods in the seat bean (with session scope):
//1st method called...removes old entries...
public void checkAndRemove(int newEmpId)
throws SQLException {
int oldSeat = 0;
try{
Connection conn = connectionPool.getConnection();
Statement qs = conn.createStatement();
ResultSet rs = qs.executeQuery("SELECT id FROM seat WHERE" +
" id <> " + this.id + " AND emp_id = " + newEmpId +
" AND editable = " + QUOTE + "y" + QUOTE);
if(rs.next()) {
oldSeat = rs.getInt(1);
rs.close();
qs.close();
if(oldSeat > 0) {
qs = conn.createStatement();
rs = qs.executeQuery("SELECT COUNT(emp_id) FROM seat WHERE " +
"id = "+ oldSeat);
int cnt = rs.getInt(1);
rs.close();
qs.close();
Statement us = conn.createStatement();
if (cnt > 1) { //Is there more than 1 person at this old seat?
//If so, we can delete this entry...
us.executeUpdate("DELETE FROM seat" +
" WHERE id = " + oldSeat + " AND emp_id = " + newEmpId);
else {
us.executeUpdate("UPDATE seat SET emp_id = 0,note= " + QUOTE + " " + QUOTE + " WHERE id = " + oldSeat + " AND emp_id = " + newEmpId);
us.close();
connectionPool.close(conn);
catch(SQLException ex) {
ex.printStackTrace();
throw ex;
//2nd method called, updates the seat with new emp...
/**updateSeat updates seat information */
public void updateSeat(int newEmpId, String newNote)
throws SQLException {
java.util.Date dt = new java.util.Date();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String timestamp = sdf.format(dt);
newNote = escape(newNote); //escape any ' in the text...
try{
Connection conn = connectionPool.getConnection();
Statement us = conn.createStatement();
us.executeUpdate("UPDATE seat SET " +
" emp_id= " + newEmpId + COMMA +
"Note= " + QUOTE + newNote + QUOTE + COMMA +
"Timestamp= " + QUOTE + timestamp + QUOTE +
"WHERE seat.id = " + this.id + "AND seat.emp_id = " + this.empId);
us.close();
connectionPool.close(conn);
catch(SQLException ex) {
ex.printStackTrace();
throw ex;
The seat table has a primary key of id/emp_id.
Like I said, these queries have worked fine on a different installation, and they work sporadically on this one. Any clues about this? Could some sort of 'timeout' be occuring and not throwing any errors?
Any ideas/help would be greatly appreciated...
Thanks, Mike

Answer 1

Sorry. Let me clarify... While this app fails to properly insert into the database, the rest of the app functions as normal.
Basically, when I click on a hotspot, I open a small window with javaScript. The window has a form that I fill out with emp info, then I submit it and it closes. Then, when someone clicks on that hotspot, the record that should have been created displays...
This works some of the time, but when it doesn't, it simply displays a blank form, and based on a report run on another page, I know that it never inserted/updated the database. But never any error messages, etc.
Mike