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How to check if the inputted data exist in database

I would like to know if what am I lacking here, I can't compare the 'id' from the Textfield to the data from the database.
For example:
If TextField1 == to the data in the database.
Output: Swept by GSW.
Connection con = connect.getConnection();
String query = "SELECT * FROM item_list WHERE id = ?";
Statement st;
ResultSet rs;
int id;
try{
st = con.createStatement();
rs = st.executeQuery(query);
while(rs.next()){
id = rs.getInt("id");
if(Integer.parseInt(TF[0].getText()) == id){
System.out.println(id);
}
}
}catch(SQLException exc){
System.out.println("Not Found!");
}
Kindly Check the Image Output.
I attached the image file below.
Sample Output

Here are some mistake I see
You use a parameter in the query, "SELECT * FROM item_list WHERE id = ?";so use a PreparedStatement
Set the parameter to that PreparedStatement ps = connection.preparedStatement(query); with ps.setInt(1, Integer.parseInt(TF[0].getText()));
Don't catch the exception without logging it, here your query as a syntax error but you don't know it.
careful with uppercase in the database field name "Id"
This might not be everything ...
And of course, now that you get only the row with that ID, you can simply check if there is at least one row return to validate that it exists.

First of all, you need to log a stack trace of an exception that is thrown. At least you can use exc.printStackTrace() in your catch section.
Second, your issue is that you declared a parameter for your SQL query, but you have not put any value to it.
PreparedStatement p = con.prepareStatement("SELECT * FROM item_list WHERE id = ?");
p.setString(1, TF[0].getText() ); //VALUE_FROM_YOUR_TEXT_INPUT
You don't need to iterate over all result set to check if a user with such id exists. You can just check that result set is not empty.

you can use intValue() for Integer object obvious if your object is not null
while(rs.next()){
id = rs.getInt("id");
if(Integer.parseInt(TF[0].getText()).intValue() == id){
System.out.println(id);
}
}

You're not setting the value of the id parameter in the statement. Not familiar with Java but in C# it would be something like
statement.Parameters.AddWithValue("#id", id)

Thank You guys! I've been trying and reading all your suggestions, and I've found and debugged it. Thanks to the one said that I need to check what message I can get in the catch.
Appreciated all your help.
Connection con = connect.getConnection();
String query = "SELECT * FROM item_list";
Statement st;
ResultSet rs;
int id;
try{
st = con.createStatement();
rs = st.executeQuery(query);
while(rs.next()){
id = rs.getInt("id");
if(Integer.parseInt(TF[0].getText()) == id){
System.out.println(id);
JOptionPane.showMessageDialog(null, "FOUND!");
}
else{
JOptionPane.showMessageDialog(null, "Not Found!");
}
}
}catch(SQLException exc){
JOptionPane.showMessageDialog(null, exc.getMessage());
}
ID Found!

Prepared statement executeUpdate is not working with update statement

Im using the following code to change password using update query of postgres.
#POST
#Path("/changepassword")
#Consumes(MediaType.APPLICATION_JSON)
public String changePassword(String msg) {
JSONObject jsonObject = new JSONObject(msg);
String songString = null;
String query = null;
PreparedStatement stmt = null;
try {
if (UserManagement.authMail(jsonObject.getString("mail"))) {
songString = Utilities.constructJSON("welcome", true);
Connection connection = MyResource.getConnection();
query = "UPDATE users SET password = '" + jsonObject.getString("password") + "' WHERE mail = ' "
+ jsonObject.getString("mail") + "'";
stmt = connection.prepareStatement(query);
stmt.executeUpdate();
songString = Utilities.constructJSON("Password reset successfull", true);
} else {
songString = Utilities.constructJSON("Please check your mail address", true);
}
} catch (Exception ex) {
songString = Utilities.constructJSON("" + query + ex, true);
}
return songString;
}
It is not effecting the database. why is that so? my connection is in auto commit mode but still it is not updating. How can I be able to sort this out?

This may help you:
Connection connection = MyResource.getConnection();
query = "UPDATE users SET password = ? WHERE mail = ?";
stmt = connection.prepareStatement(query);
stmt.setString(1,jsonObject.getString("password"));
stmt.setString(2,jsonObject.getString("mail"));
stmt.executeUpdate();
And Also be sure jsonObject.getString("password") and jsonObject.getString("mail") is getting some value.

The query contains an additional whitespace at the mail parameter, this could result in the query not returning any rows.
UPDATE users SET password = 'Password' WHERE mail = ' mailadress'
Try removing the whitespace and see if this affects the database.
Also it is preferable to use a prepared statement as mentioned in the answer provided by Keval Pithva

When you create the connection just make :
con.setAutoCommit(true);
This will help you.

Java: SQL Query: rs.next() is false after updating a column

I have a strange problem. I have a database and I want to change the values of a column. The values are safed in an Arraylist (timelist).
In order to write the values in the right row, I have a second Arrylist (namelist). So I want to read the first row in my Database, than I check the namelist and find the name. Than i take the matching value out of the timelist and write it into the database into the column "follows_date" in the row, matching to the name.
And than I read the next row of the Database, until there are no more entries.
So the strange thing is, if I change nothing in the database, the while(rs.next()) part works.
For example:
ResultSet rs = statement.executeQuery("SELECT username FROM users");
while(rs.next()){
// read the result set
String name = rs.getString("username");
System.out.println("username = " + name); //liest die namen
}
}
This would print me every name after name. But when I change the table, the while loop ends after that. (no error, the program just finishes)
ResultSet rs = statement.executeQuery("SELECT username FROM users");
while(rs.next()){
// read the result set
String name = rs.getString("username");
System.out.println("username = " + name); //writes the name
//look, if name is in Arraylist "namelist"). if yes, than write the matching date from "timelist" into the database.
if (namelist.contains(name)){
System.out.println("name found: "+ name);
int listIndizi = namelist.indexOf(name); //get index
Long indiziDatum = (long) timelist.get(listIndizi); //get date from same Index
System.out.println(indiziDatum); // print date so i can see it is correct (which it is)
statement.executeUpdate("UPDATE users SET follows_date ="+ indiziDatum +" WHERE username = '"+name+"'"); //updates the follows_date column
}
}
Everything works fine, except that now, the while loop doesn't continues after the first passage, but ends.

The resultSet of a statement is closed and will not return further results if you execute another statement. Create a new separate statement object for the update and everything should work as excepted.
Statement statement1 = connection.createStatement();
Statement statement2 = connection.createStatement();
ResultSet resultSet1 = statement1.executeQuery("SELECT username FROM users");
while(resultSet1.next()){
...
statement2.executeUpdate("UPDATE users ..."));
}

As to Why it happens:
Here is the explanation from the official documentation:
A ResultSet object is automatically closed when the Statement object that generated it is closed, re-executed, or used to retrieve the next result from a sequence of multiple results.
Alternative Approach:
From your sample, it seems you are trying to update the "same" row in your resultSet, you should consider using an Updatable ResultSet.
Sample code from the official documentation:
public void modifyPrices(float percentage) throws SQLException {
Statement stmt = null;
try {
stmt = con.createStatement();
stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
ResultSet.CONCUR_UPDATABLE);
ResultSet uprs = stmt.executeQuery(
"SELECT * FROM " + dbName + ".COFFEES");
while (uprs.next()) {
float f = uprs.getFloat("PRICE");
uprs.updateFloat( "PRICE", f * percentage);
uprs.updateRow();
}
} catch (SQLException e ) {
JDBCTutorialUtilities.printSQLException(e);
} finally {
if (stmt != null) { stmt.close(); }
}
}

setString for prepared statement not working

I am trying to use the setString(index, parameter) method for Prepared Statements in order to create a ResultSet but it doesn't seem to be inserting properly. I know the query is correct because I use the same one (minus the need for the setString) in a later else. Here is the code I currently have:
**From what I understand, the ps.setString(1, "'%" + committeeCode + "%'"); is supposed to replace the ? in the query but my output says otherwise. Any help is appreciated.
public String getUpcomingEvents(String committeeCode) throws SQLException{
Context ctx = null;
DataSource ds = null;
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
StringBuilder htmlBuilder = new StringBuilder();
String html = "";
try {
ctx = new InitialContext();
ds = (DataSource) ctx.lookup("java:ConnectDaily");
conn = ds.getConnection();
if(committeeCode != null){
//get all events
String queryStatement = "SELECT " +
.......
"WHERE c.calendar_id = ci.calendar_id AND c.short_name LIKE ? " +
"AND ci.style_id = 0 " +
"AND ci.starting_date > to_char(sysdate-1, 'J') " +
"AND ci.item_type_id = cit.item_type_id " +
"ORDER BY to_date(to_char(ci.starting_date), 'J')";
ps = conn.prepareStatement(queryStatement);
ps.setString(1, "'%" + committeeCode + "%'");
System.out.println(queryStatement);
rs = ps.executeQuery();
if (rs != null){
while(rs.next()){
String com = rs.getString("name");
String comID = rs.getString("short_name");
String startTime = rs.getString("starting_time");
String endTime = rs.getString("ending_time");
String name = rs.getString("contact_name");
String desc = rs.getString("description");
String info = rs.getString("contact_info");
String date = rs.getString("directory");
htmlBuilder.append("<li><a href='?com="+committeeCode+"&directory=2014-09-10'>"+com+" - "+ date +" - "+startTime+" - "+endTime+"</a> <!-- Link/title/date/start-end time --><br>");
htmlBuilder.append("<strong>Location: </strong>"+comID+"<br>");
htmlBuilder.append("<strong>Dial-In:</strong>"+com+"<br>");
htmlBuilder.append("<strong>Part. Code:</strong>"+info+"<br>");
htmlBuilder.append("<a href='http://nyiso.webex.com'>Take me to WebEx</a>");
htmlBuilder.append("</li>");
}
}
html = htmlBuilder.toString();
.
.
.
}catch (NamingException e) {
e.printStackTrace();
//log error and send error email
} catch (SQLException e) {
e.printStackTrace();
//log error and send error email
}finally{
//close all resources here
ps.close();
rs.close();
conn.close();
}
return html;
}
}
Output
14:18:22,979 INFO [STDOUT] SELECT to_char(to_date(to_char(ci.starting_date), 'J'),'mm/dd/yyyy') as start_date, to_char(to_date(to_char(ci.ending_date), 'J'),'mm/dd/yyyy') as end_date, to_char(to_date(to_char(ci.starting_date), 'J'),'yyyy-mm-dd') as directory, ci.starting_time, ci.ending_time, ci.description, cit.description as location, c.name, c.short_name, ci.add_info_url, ci.contact_name, ci.contact_info FROM calitem ci, calendar c, calitemtypes cit WHERE c.calendar_id = ci.calendar_id AND c.short_name LIKE ? AND ci.style_id = 0 AND ci.starting_date > to_char(sysdate-1, 'J') AND ci.item_type_id = cit.item_type_id ORDER BY to_date(to_char(ci.starting_date), 'J')

There is no need for the quotes in setString:
ps.setString(1, "%" + committeeCode + "%");
This method will bind the specified String to the first parameter. It will not change the original query String saved in queryStatement.

The placeholder remains as part of the SQL text.
The bind value is passed when the statement is executed; the actual SQL text is not modified. (This is one of the big advantages of prepared statements: the same exact SQL text is reused, and we avoid the overhead of a hard parse.
Also note that you are including single quotes within the value, which is a bit odd.
If the bind placeholder were to be replaced in the SQL text, assuming committeeCode contains foo, the equivalent SQL text would be:
AND c.short_name LIKE '''%foo%'''
which will match only c.short_name values that begin and end with a single quote, and contain the string foo.
(This looks more like Oracle SQL syntax than it does MySQL.)

As we know that in setString we can pass string value only, So even if we write the code like this:
String param="'%"+committeeCode+"%'";
And if you print the value of param it will throw error, Hence you cannot use it as well in prepared statement.
You need to modify modify it little bit as:
String param="%"+committeeCode+"%";(Simpler one, other way can be used)
ps.setString(1,param);

SQL command from eclipse using JDBC

I have been searching and trying different stuff for awhile, but have not found an answer. I'm trying to make a connection to sql using JDBC from eclipse. I am having trouble when I need to select a string in the database. If I use:
Select name from data where title = 'mr';
That works with terminal/command line but when I try to use eclipse where I use
statement sp = connection.createstatement();
resultset rs = sp.executequery("select name from data where title = '" + "mr" + "'");
It does not give me anything while the terminal input does. What did I do wrong in the eclipse? Thanks
Heres a part of the code. Sorry, its a bit messy, been trying different things.
private boolean loginChecker(String cid, String password) throws SQLException{
boolean check = false;
PreparedStatement pstatment = null;
Statement stmt = null;
//String query = "SELECT 'cat' FROM customer";
String query = "select '"+cid+"' from customer where password = '"+password+"'";
try {
System.out.println("in try......");
//stmt = con.createStatement();
//ResultSet rs = stmt.executeQuery(query);
PreparedStatement prepStmt = con.prepareStatement(query);
ResultSet rs = prepStmt.executeQuery();
//System.out.print(rs.getString("cid"));
while(rs.next()){
check = true;
System.out.print(rs.getString("cid"));
}
} catch (SQLException e ) {
e.printStackTrace();
} finally {
if (stmt != null) {
//stmt.close();
}
}
return check;
}
Second try on a simpler query:
public List<Object> showTable() {
List<Object> result = new ArrayList<Object>();
String name = "bob";
try
{
PreparedStatement preStatement = con.prepareStatement("select total from test where name = ?");
preStatement.setString(1, name);
ResultSet rs1 = preStatement.executeQuery();
while(rs1.next()){
System.out.println("there");
System.out.println(rs1.getInt("total"));
}
}
catch (SQLException ex)
{
System.out.print("Message: " + ex.getMessage());
}
return result;
}

Remove the quotes around the column name.
String query = "select "+cid+" from customer where password = '"+password+"'";
You've not mentioned which database you're working with but many databases like Oracle change the column case to upper case unless they're quoted. So, you only quote table columns if that's how you had created them. For example, if you had created a table like
CREATE TABLE some_table ( 'DoNotChangeToUpperCase' VARCHAR2 );
Then you would have to select the column with quotes as well
SELECT 'DoNotChangeToUpperCase' FROM some_table
But, if you didn't create the table using quotes you shouldn't be using them with your SELECTs either.

Make sure you are not closing the ResultSet before you are trying to use it. This can happen when you return a ResultSet and try to use it elsewhere. If you want to return the data like this, use CachedRowSet:
CachedRowSet crs = new CachedRowSetImpl();
crs.populate(ResultSet);
CachedRowSet is "special in that it can operate without being connected to its data source, that is, it is a disconnected RowSet object"
Edit: Saw you posted code so I thought I add some thoughts. If that is your ACTUAL code than the reason you are not getting anything is because the query is probably not returning anything.
String query = "select '"+cid+"' from customer where password = '"+password+"'";
This is wrong, for two reasons. 1) If you are using prepared statements you should replace all input with '?' so it should look like the following:
String query = "select name from customer where password = ?";
Then:
PreparedStatement prepStmt = con.prepareStatement(query);
prepStmt.setString(1, password);
ResultSet rs = prepStmt.executeQuery();
2)
System.out.print(rs.getString("cid"));
Here are are trying to get the column named "cid", when it should be the name stored in cid. You should actually never be letting the user decide what columns to get, this should be hardcoded in.