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how to sort a table from database

I want to be able to sort a table from the database, according to either the quatity or the name, but how do i decided what happens in what case?
Below is the code for the table.
public void tableupdate(JTable jTable1, String fill) {
try {
try {
Class.forName("org.h2.Driver");
Connection con = DriverManager.getConnection("jdbc:h2:file:D:/Inventory.db", "sa", "");
Statement stat = con.createStatement();
fill = "SELECT * FROM BOOKDESC ";
ResultSet rs = stat.executeQuery(fill);
while (jTable1.getRowCount() > 0) {
((DefaultTableModel) jTable1.getModel()).removeRow(0);
}
int columns = rs.getMetaData().getColumnCount();
while (rs.next()) {
Object[] row = new Object[columns];
for (int i = 1; i <= columns; i++) {
row[i - 1] = rs.getObject(i);
}
((DefaultTableModel) jTable1.getModel()).insertRow(rs.getRow() - 1, row);
}
rs.close();
stat.close();
con.close();
} catch (ClassNotFoundException e) {
JOptionPane.showMessageDialog(null, e);
}
} catch (SQLException e) {
JOptionPane.showMessageDialog(null, e);
}
}

MySQL is offering a method for sorting data in your SELECT statement, it's called ORDER BY.
Usage is found here.
This way, your code doesn't have to do the work, as your ResultSet already gets sorted data.

Looping try/catch statement

I'm trying to take two random rowid from my database. Everything works but I have a scenario when there is only one rowid. I want to make a loop on my try/catch until there is second number in my database.
What I'm doing wrong? Thank you
public void Kaslaimejo() {
String sql = "SELECT rowid FROM Zaidejai WHERE Pirmas < 4 ORDER BY random() LIMIT 2";
Integer value1 = null, value2 = null;
Integer judesiukas1 = null, judesiukas2 = null;
int a = 0;
int k = 15; // kiek kartu? Reikia infinity padaryti
for (a = 0; a < 3; a++) {
try {
Connection conn = Serveris.connect();
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery(sql)) {
if (rs.next()) {
value1 = rs.getInt("rowid");
if (rs.next()) {
value2 = rs.getInt("rowid");
PreparedStatement buvo = conn.prepareStatement("UPDATE Zaidejai SET Numeriukas = ? WHERE rowid = ?");
buvo.setInt(1, i);
buvo.setInt(2, value1);
int buvolala = buvo.executeUpdate ();
PreparedStatement buvo2 = conn.prepareStatement("UPDATE Zaidejai SET Numeriukas = ? WHERE rowid = ?");
buvo2.setInt(1, i);
buvo2.setInt(2, value2);
int buvolala2 = buvo2.executeUpdate ();//
i++;
}
System.out.println("Pirmas zaidejas" + value1); // atspausdina 1 random zaideja is duomenu bazes
System.out.println("Antras zaidejas" + value2); // atspausdina 2 random zaideja is duomenu bazes
}
} catch (SQLException e) {
a--;
//System.out.println(e.getMessage());
}
}
}
Right now my program loops two times and then gives me SQLException. How I can loop my program until there is no SQLException?

OK, I've tried to write what I think you're trying to do.
You wait for ever until someone puts at least two entries in the database.
You extract two values, process them, then wait some more.
Some points to watch out:
1. Object comparisons need to be made with .equals() not with ==
2. You might want to provide some way to break out of the infinite loop I've written (while(true)).
3. Careful with null values. They might produce NullPointerException.
4. Try to break up your code into methods. Each large block of code could go into each own method.
public void Kaslaimejo(){
String sql = "SELECT rowid FROM Zaidejai WHERE Pirmas < 4 ORDER BY random() LIMIT 2";
Integer judesiukas1 = null, judesiukas2 = null;
while(true) {
List<Integer> values = new ArrayList<>();
while (values.size() < 2) {
try (Connection conn = Serveris.connect();
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery(sql)) {
if( rs.next() ){
Integer value = rs.getInt("rowid");
values.add(value);
}
} catch (SQLException e) {
e.printStackTrace();
}
}
try( Connection conn = Serveris.connect()) {
PreparedStatement buvo = conn.prepareStatement("UPDATE Zaidejai SET Numeriukas = ? WHERE rowid = ?");
buvo.setInt(1, i);
buvo.setInt(2, values.get(0));
int buvolala = buvo.executeUpdate ();
PreparedStatement buvo2 = conn.prepareStatement("UPDATE Zaidejai SET Numeriukas = ? WHERE rowid = ?");
buvo2.setInt(1, i);
buvo2.setInt(2, values.get(1));
int buvolala2 = buvo2.executeUpdate ();//
i++;
}catch (SQLException e) {
e.printStackTrace();
}
Connection conn = Serveris.connect();
try {
PreparedStatement pstmt = conn.prepareStatement("SELECT Pirmas FROM Zaidejai WHERE rowid = ?");
PreparedStatement pstmt2 = conn.prepareStatement("SELECT Pirmas FROM Zaidejai WHERE rowid = ?");
pstmt.setInt(1, values.get(0));
pstmt2.setInt(1, values.get(1));
ResultSet myrsv = pstmt.executeQuery();
ResultSet myrsv2 = pstmt2.executeQuery();
{
if (myrsv.next()) {
judesiukas1 = myrsv.getInt("Pirmas");
if (myrsv2.next()) {
judesiukas2 = myrsv2.getInt("Pirmas");
}
}
//System.out.println("Pirmo zaidejo veiksmas" + myrsv.getInt("Pirmas"));
//System.out.println("Antro zaidejo veiksmas" + myrsv2.getInt("Pirmas"));
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if (judesiukas1.equals(judesiukas2)) // careful here. NullPointerException may happen.
{
try {
PreparedStatement laim = conn.prepareStatement("UPDATE Zaidejai SET Rezultatas = ? WHERE rowid = ?"); // ble ble update reikia naudoti , o ne insert into. Insert kai sukuriame nauja kazka tik
PreparedStatement laim2 = conn.prepareStatement("UPDATE Zaidejai SET Rezultatas = ? WHERE rowid = ?");
laim.setString(1, "Lygiosios");
laim.setInt(2, values.get(0));
laim2.setString(1, "Lygiosios");
laim2.setInt(2, values.get(1));
int irasyk = laim.executeUpdate (); // kodel executeupdate, o ne executequery????
int irasyk2 = laim2.executeUpdate (); // kodel executeupdate, o ne executequery????
{
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.print("Lygiosios");
} else {
// (1) - Rock
// (2) Scissors
// (3) - Paper
switch (values.get(0)){
case 1:
if (judesiukas2 == 2)
System.out.print("Zaidejas 1 wins!");
else
System.out.print("Zaidejas 2 wins!");
break;
case 2:
if (judesiukas2 == 3)
System.out.print("Zaidejas 1 wins!");
else
System.out.print("Zaidejas 2 wins!");
break;
case 3:
if (judesiukas2 == 1)
System.out.print("Zaidejas 1 wins!");
else
System.out.print("Zaidejas 2 wins!");
break;
}
}
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

The logic becomes easier if you add the values to a list
var values = new ArrayList<Integer>();
while (values.Count < 2) {
try (Connection conn = Serveris.connect();
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery(sql))
{
while (values.Count < 2 && rs.next()) {
Integer v = rs.getInt("rowid");
values.Add(v);
}
} catch (SQLException e) {
}
}
//TODO: process the values here
The advantage is, that you can retrieve one value at the first database query and the second at a later one or both in the same round and you don't have to keep track of which one of two variables to use.
(Bear with me with the syntax details, I'm not a Java programmer.)

How i can loop my program until there is no SQLException?
Change this (because, it will only allow to loop two times)
for (a = 0; a < 2; a++) {
to
while(true)
Put everything inside while(true), if exception occurred, then it will come out from the while loop. Something similar :
try
{
while(true)
{
...
...
}
...
}
catch(SQLException e)
{
// do somthing
}

Can i have two connection statement in a single button action performed using java swing.?

My complete code to access data from two different databases using single hive jdbc driver. I get sql exception on next database connection, before that it works perfectly. Kindly, suggest me some solution to further process. Where as next prepared statement query throws sql exception. But doing on a separate button action it works fine, while i'm doing in a single action it throws error.
String s1 = jTextField1.getText();
String s2 = jTextField2.getText();
String s3 = jTextField3.getText();
String s4 = new String(jPasswordField1.getPassword());
try {
Class.forName("org.apache.hive.jdbc.HiveDriver");
Connection con = DriverManager.getConnection("jdbc:hive2://localhost:10000/twitter_db", "arunachalam", "");
Statement st = con.createStatement();
String sql = "select dbname,tbname from check where userid='" + s3 + "'and tbname='" + s2 + "'";
String sql1 = "select userid,password from user_reg where userid='" + s3 + "'";
ResultSet rs = st.executeQuery(sql);
try {
PreparedStatement ps = con.prepareStatement(sql1);
ResultSet rs1 = ps.executeQuery();
while (rs.next() && rs1.next()) {
if ((rs.getString("dbname").equals(s1)) && (rs.getString("tbname").equals(s2)) && (rs1.getString("userid").equals(s3)) && (rs1.getString("password").equals(s4))) {
jSeparator1.setVisible(true);
jScrollPane1.setVisible(true);
try {
Connection con1 = DriverManager.getConnection("jdbc:hive2://localhost:10000/" + s1, "arunachalam", "");
ArrayList<Tweet> list = new ArrayList<Tweet>();
String ve = "select id,created_at,source,favorited,retweet_count,retweeted_status,entities,text,user,in_reply_to_screen_name from " + s2;
PreparedStatement ps1 = con1.prepareStatement(ve);
ResultSet rs2 = ps1.executeQuery();
Tweet tweet;
while (rs2.next()) {
tweet = new Tweet(rs.getLong("id"), rs.getString("created_at"), rs.getString("source"), rs.getBoolean("favorited"), rs.getInt("retweet_count"), rs.getString("retweeted_status"), rs.getString("entities"), rs.getString("text"), rs.getString("user"), rs.getString("in_reply_to_screen_name"));
list.add(tweet);
String[] columnName = {"Tweet_ID", "Created_At", "Source", "Favorited", "Retweet_Count", "Retweeted_Status", "Entities", "Text", "User", "Screen_Name"};
Object[][] twt = new Object[list.size()][10];
for (int i = 0; i < list.size(); i++) {
twt[i][0] = list.get(i).gettweetid();
twt[i][1] = list.get(i).getcreated();
twt[i][2] = list.get(i).getsource();
twt[i][3] = list.get(i).getfavor();
twt[i][4] = list.get(i).getcount();
twt[i][5] = list.get(i).getstatus();
twt[i][6] = list.get(i).getentities();
twt[i][7] = list.get(i).gettext();
twt[i][8] = list.get(i).getuser();
twt[i][9] = list.get(i).getscreen();
TheModel model = new TheModel(twt, columnName);
jTable1.setModel(model);
jTable1.setRowHeight(20);
}
}
} catch (Exception e) {
showMessageDialog(null, e);
}
break;
} else if ((!rs.getString("dbname").equals(s1)) && (rs.getString("tbname").equals(s2)) && (rs1.getString("userid").equals(s3)) && (rs1.getString("password").equals(s4))) {
JOptionPane.showMessageDialog(null, "Database Name is Incorrect", "Error", JOptionPane.ERROR_MESSAGE);
break;
} else if ((rs.getString("dbname").equals(s1)) && (!rs.getString("tbname").equals(s2)) && (rs1.getString("userid").equals(s3)) && (rs1.getString("password").equals(s4))) {
JOptionPane.showMessageDialog(null, "Table Name is Incorrect", "Error", JOptionPane.ERROR_MESSAGE);
break;
} else if ((rs.getString("dbname").equals(s1)) && (rs.getString("tbname").equals(s2)) && (rs1.getString("userid").equals(s3)) && (!rs1.getString("password").equals(s4))) {
JOptionPane.showMessageDialog(null, "Password is Incorrect", "Error", JOptionPane.ERROR_MESSAGE);
break;
} else if ((!rs1.getString("userid").equals(s3)) && (rs.getString("dbname").equals(s1)) && (rs.getString("tbname").equals(s2)) && (rs1.getString("password").equals(s4))) {
JOptionPane.showMessageDialog(null, "User ID is Incorrect", "Error", JOptionPane.ERROR_MESSAGE);
break;
} else {
JOptionPane.showMessageDialog(null, "Access Denied", "Error", JOptionPane.ERROR_MESSAGE);
}
}
} catch (Exception e) {
showMessageDialog(null, e);
}
} catch (Exception e) {
showMessageDialog(null, e);
}

To be responsive, as the application would freeze during actionPerformed use
invokeLater.
Yes separate connections for instance with different users, one for reading only, one for admin tasks, is quite possible. However I did not see calls to close().
(Also a single-user (such as an embedded) database might not do.)
To automatically close connection, statement and result set use try-with-resources: try (DECLARATION; ... ; DECLARATION) { ... } - saves a lot.
The explicit class loading with Class.forName no longer is needed for current drivers.
// Java 8
SwingUtilities.invokeLater(() -> {
String sql = "select dbname, tbname from check where userid=? and tbname=?";
try (Connection con = DriverManager.getConnection(
"jdbc:hive2://192.168.1.13:10000/twitter_db", "arunachalam", "");
PreparedStatement st = con.prepareStatement(sql)) {
st.setString(1, s3);
st.setString(2, s2);
try (ResultSet rs = st.executeQuery()) {
if (rs.next()) {
List<Tweet> list = new ArrayList<>();
String hive = "select id,created_at,source,favorited,retweet_count,"
+ "retweeted_status,entities,text,user,in_reply_to_screen_name from "
+ s2;
try (Connection con1 = DriverManager.getConnection(
"jdbc:hive2://localhost:10000/"+s1, "arunachalam", "");
PreparedStatement ps1 = con1.prepareStatement(hive);
ResultSet rs2 = ps1.executeQuery()) {
...
});

to check whether the search element isn't available in DB

I'm using phpmy admin and I need to Display "Not Found" message in case searching element is not found in the DB.
Used code is here.
Connection c = DBconnect.connect();
Statement s = c.createStatement();
String e = txtempId.getText();
ResultSet rs = s.executeQuery("SELECT * FROM nonacademic WHERE empId='" +e+ "'");
I used this method to search empId ,if empId is not available in db I need to display a message.Please give me a solution how to detect, if empId is not available in DB.

if (rs != null)
{
out.println("result set has got something");
while (rs.next())
{
//I am processing result set now
}
}
else
{
out.println("Not Found");
}

Use if statement like this
Connection c = DBconnect.connect();
Statement s = c.createStatement();
String e = txtempId.getText();
ResultSet rs = s.executeQuery("SELECT * FROM nonacademic WHERE empId='" +e+ "'");
if(rs.next())
{
do
{
// If there is data, then process it
}
while(rs.next());
}
else
System.out.println("Not Found");

Added parse of text to integer, assuming empId is an integer.
int empId = Integer.parseInt(txtempId.getText());
try (Connection c = DBconnect.connect()) {
String sql = "SELECT *" +
" FROM nonacademic" +
" WHERE empId = ?";
try (Statement s = c.prepareStatement(sql)) {
s.setInt(1, empId);
try (ResultSet rs = s.executeQuery()) {
if (! rs.next()) {
// not found
} else {
// found, call rs.getXxx(...) to get values
}
}
}
}

Just use the basic simple if & else statement. If the ResultSet is "null" or it doesn't contain any record display the Message otherwise read data & display.
Connection c = DBconnect.connect();
Statement s = c.createStatement();
String e = txtempId.getText();
ResultSet rs = s.executeQuery("SELECT * FROM nonacademic WHERE empId='" +e+ "'");
if(rs.next())
// record found do the processing
else
System.out.println("Not Found");

String e = txtempId.getText();
String sql="select *from nonacademic where empId='"+ e+"' ";
try {
boolean status=DatabaseConnection.checkValue(sql);
if (status) {
JOptionPane.showMessageDialog(null,
"This id is available");
} else {
JOptionPane.showMessageDialog(null,
"Not found");
}
} catch (Exception e) {
}
This method return check whether the search element is exist or not
public static boolean checkValue(String sql) throws Exception {
boolean b = false;
ResultSet rst = null;
Statement st = getStatement();
rst = st.executeQuery(sql);
if (rst.next()) {
b = true;
}
return b;
}

Getting empty resultSet for simple query

gurus,
I am new to Java SQL, and need some help.
I'm trying to get a parameter from MS SQL Server 2008. The data is definitely there - it is a current and valid DB, and I'm trying to use the users records to get cridentials for another application.
I asserted the following query:
String query = "SELECT [USER].qc_number FROM [USER] WHERE "[USER].login_name = '"
+ userNameInput + "' AND [USER].password = '" + passWordInput + "';";
Where userNameInput and passWordInput are received from the user. The URL, query and driver class are definitely correct: I checked the DB schema both from the application and from the server views. Furthermore, I verified all the Exceptions systems by changing parameters one by one, resulting in correct Exceptions messages. However, I get a resultSet with 1 column and 0 rows.
The code is below:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class trOdbc
{// database URL
final String DB_URL = "***";
final String Class_URL = "com.microsoft.sqlserver.jdbc.SQLServerDriver";
private Connection connection = null; // manages connection
private Statement statement = null; // query statement
private ResultSet resultSet = null; // manages results
private Boolean connectedToDatabase = false;
// ----------------------------------------------------------
public void createJdbcConnection()
{ // connect to database books and query database
if (connectedToDatabase)
{ return; }
try
{ // connectedToDatabase is false - establish the connection
Class.forName(Class_URL);
connection = DriverManager.getConnection
(DB_URL, "***", "***" );
statement = connection.createStatement
(ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY);
connectedToDatabase = true;
}
catch (SQLException ex)
{ System.out.println ("SQL Exception in connection establishment: " + ex); }
catch (ClassNotFoundException ex)
{ System.out.println ("Class not found exception in query process: " + ex); }
}
// ----------------------------------------------------------
public String [][] processJdbcQuery (String query)
{
createJdbcConnection ();
if (!connectedToDatabase)
{ return null; }// the connection wasn't established
try
{// query database
resultSet = statement.executeQuery(query);
int columns = resultSet.getMetaData().getColumnCount();
int rows = 0;
if (resultSet != null)
{
resultSet.beforeFirst();
resultSet.last();
rows = resultSet.getRow();
}
String [][] tempData = new String[rows][columns];
resultSet.beforeFirst();
rows = 0;
while (resultSet.next())
{
for (int x = 1; x <= columns; x++)
{
tempData [rows][x - 1] = resultSet.getString (x);
}
rows++;
}
CloseJdbcConnection ();
return tempData;
}
catch (SQLException ex)
{
System.out.println ("SQL Exception in query process: " + ex);
CloseJdbcConnection ();
return null;
}
} // end processJdbcQuery
// ----------------------------------------------------------
public void CloseJdbcConnection()
{
if ( connectedToDatabase )
{// close Statement and Connection. resultSet is closed automatically.
try
{
statement.close();
connection.close();
connectedToDatabase = false;
}
catch (SQLException ex)
{ System.out.println ("SQL Exception in connection closure: " + ex); }
} // end if
} // end method CloseJdbcConnection
} // end class trOdbc

Why don't you use Prepared Statement instead ?
Here is a good tutorial for using prepared statement in java
In your case it would be :
String query = "SELECT [USER].qc_number FROM [USER] " +
"WHERE [USER].login_name = ? AND [USER].password = ?;";
And then set it with different values each time you execute it like :
PreparedStatement ps = connection.prepareStatement(query);
ps.setString(1, userNameInput);
ps.setString(2, passWordInput);
resultSet = ps.executeQuery();