Develop Reference

Problem with Update query in Mysql with JDBC

see the screenshots
see the 2nd screenshot
see the 3rd screenshot
Okay so I am building a project on java and mysql, I am stuck at this point that I have to update a data which is in MySql but from my java gui application, I've executed that update command from MySql command line client
update user set bldu = 50 where userid = 1001;
and it's working perfectly fine there but from my java application on clicking on assigned jbutton it says:
you have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'userid= 1001' at line 1
Please help me..!

In your first screenshot you must add a space before WHERE clause:
String query = "UPDATE user SET bdlu = " + bldut + "WHERE userid = " + uid + ";";
So your query will be interpretated as:
UPDATE user SET bdlu = 50WHERE userid = 1001
So you'll raise a syntax error.
Then you'll have the following query:
String query = "UPDATE user SET bdlu = " + bldut + " WHERE userid = " + uid + ";";

String query = "update user SET bldu = " + bldut + " WHERE userid = " + uid + ";";
use this one instead of your old query may be it is helpful for you.

Try this snippet in your code.
String query = "update user SET bldu = " + bldut + " WHERE userid = " + uid + ";";
Statement = con.prepareStatement(query);
Statement.executeUpdate();
by looking at your code you cannot store results of update query in resultSet the executeUpdate() only return 0 or 1 for success and failure of Update.

Okay i guys i have figured out something that it is working i mean this program is updating the data stored in mysql from netbeans via jdbc but it won't stop showing that error message like:
"Can not issue data manipulation statements with executeQuery()"
everytime i click one that assigned jButton..! but i checked the database the value i want to change is being changed but then why it is showing this error..?

Please use this code in your java file, do changes according to your file. your issue is you are using the same query in a result set that already uses for the update
Connection conn = DriverManager.getConnection(
"jdbc:mysql://localhost:3306/bdb", "root", "root");
try {
String query = "update user SET bldu = " + bldut+ " WHERE userid = " + uid + ";";
// create the java mysql update preparedstatement
Class.forName("com.mysql.jdbc.Driver").newInstance();
PreparedStatement preparedStmt = conn.prepareStatement(query);
preparedStmt.executeUpdate();
query = "select * from user WHERE userid = " + uid +";";
ResultSet rs = stmt.executeQuery(query);
// STEP 5: Extract data from result set
while (rs.next()) {
// Retrieve by column name
String userid = rs.getString("userid");
String userfname = rs.getString("userfname");
// all your column
// Display values
System.out.print("userid: " + userid);
}
// STEP 6: Clean-up environment
rs.close();
stmt.close();
conn.close();
} catch (Exception e) {
System.err.println("Got an exception! ");
System.err.println(e.getMessage());
} finally {
// finally block used to close resources
try {
if (conn != null)
conn.close();
} catch (SQLException se) {
se.printStackTrace();
}// end finally try
}// end try

JavaFX update a Sqlite table

I am currently working on a program the function of which is to store my passwords, and this is why I am using an SQL database called Users. This database contains tables for all the users which will be using the program. Those tables have four columns:
SiteName, Username, Password, AdditionalInfo
I am having a problem updating a specific row. This is my the code I get an error with:
public static void editPassword(String user, String siteEdited, String site, String usernamej, String password, String info){
try{
System.out.println(usernamej);
Class.forName("org.sqlite.JDBC");
c = DriverManager.getConnection("jdbc:sqlite:res/Users");
c.setAutoCommit(false);
stmt = c.createStatement();
String update = "UPDATE " + user + " set Username = " + usernamej + " where SiteName = " + siteEdited;
stmt.executeUpdate(update);
stmt.close();
c.close();
}catch(Exception e){
System.err.print( e.getClass().getName() + ": " + e.getMessage());
}
}
It is in a class made specifically for dealing with the sql database and it gets the following error when I try to change the username to 'test':
java.sql.SQLException: [SQLITE_ERROR] SQL error or missing database (no such column: test)

Assuming the value you pass in for user is the name of the table, your update string is going to look like
UPDATE usertable SET Username = test where SiteName = siteEditedValue
You need to quote the string values:
UPDATE usertable SET Username = 'test' where SiteName = 'siteEditedValue'
The quick and dirty way is:
String update = "UPDATE " + user + " set Username = '" + usernamej + "' where SiteName = '" + siteEdited + "'";
However, it's much (much, much) better to use a PreparedStatement in this case:
public static void editPassword(String user, String siteEdited, String site, String usernamej, String password, String info){
try{
System.out.println(usernamej);
Class.forName("org.sqlite.JDBC");
c = DriverManager.getConnection("jdbc:sqlite:res/Users");
stmt = c.prepareStatement("UPDATE " + user + " SET Username = ? Where SiteName = ?");
stmt.setString(1, usernamej);
stmt.setString(2, siteEdited);
stmt.executeUpdate();
stmt.close();
c.close();
}catch(Exception e){
System.err.print( e.getClass().getName() + ": " + e.getMessage());
}
}
This code assumes the type of stmt is PreparedStatement, not just Statement.
As well as taking care of quoting the values for you, this will escape any sql for you, preventing the possibility of SQL-injection attacks (while these are far less of an issue in a desktop application that a web application, it's still a good habit to get into).

#griFlo I got it running with this code:
public static void editPassword(String user, String siteEdited, String site, String usernamej, String password, String info){
try{
System.out.println(usernamej);
Class.forName("org.sqlite.JDBC");
c = DriverManager.getConnection("jdbc:sqlite:res/Users");
c.setAutoCommit(false);
PreparedStatement stmt = c.prepareStatement("UPDATE " + user + " SET Username = ? Where SiteName = ?");
stmt.setString(1, usernamej);
stmt.setString(2, siteEdited);
stmt.executeUpdate(update);
c.commit();
stmt.close();
c.close();
}catch(Exception e){
System.err.print( e.getClass().getName() + ": " + e.getMessage());
}
}
I had forgotten to put c.commit();

Create and connect to an SQL database using Java

I have a Java program that connects to an SQL database, and can write and read from it, however, in order to use the program, I first have to open Workbench, and run an SQL query in there.
Obviously, this isn't a great solution, so how can I create and connect to a database all within the Java code?
I've searched online, including the Oracle site, but can't see to get it.
Below is my code.
public Connection ConnectNow() //Connect to the database
{
try
{
Class.forName("com.mysql.jdbc.Driver").newInstance();
}
catch (Exception ex)
{
System.out.println("Error 1");
ex.getMessage();
}
final String dbURL = "jdbc:mysql://localhost/game1"; //replace 'assignex' with database name
Connection conn = null;
try
{
conn = DriverManager.getConnection(dbURL, "root", "password");
System.out.println("\n== Connection Successful ==");
return conn;
}
catch (SQLException ex)
{
System.out.println("Error 2");
System.out.println("SQLException: " + ex.getMessage());
System.out.println("SQLState: " + ex.getSQLState());
System.out.println("VendorError: " + ex.getErrorCode());
return null;
}
}
public void CreateDatabase()
{
try
{
Connection conn = ConnectNow();
Statement stmt = conn.createStatement();
String createDatabase = "CREATE DATABASE IF NOT EXISTS game1"; //creates database
stmt.executeUpdate(createDatabase);
conn.close();
stmt.close();
System.out.println("<< Database created successfully >>");
}
catch (Exception ex)
{
System.out.println("Error 7");
ex.getMessage();
ex.printStackTrace();
}
}
public void CreateTable() //creates a table within the database
{
try
{
Connection conn = ConnectNow();
Statement stmt = conn.createStatement();
String createTable = "CREATE TABLE IF NOT EXISTS user" +
"(firstname VARCHAR(255), " + //AUTO_INCREMENT to add numbers automatically
" surname VARCHAR(255), " +
" day INTEGER, " +
" month INTEGER, " +
" year INTEGER, " +
" username VARCHAR(255) NOT NULL, " +
" password VARCHAR(255), " +
" PRIMARY KEY (username))";
stmt.executeUpdate(createTable);
conn.close();
stmt.close();
System.out.println("<< Table created successfully >>");
}
catch (Exception ex)
{
System.out.println("Error 6");
ex.getMessage();
ex.printStackTrace();
}
}
Presumably, it's something to do with me attempting to connect before creating the database, but I can't find the solution to implement this correctly.
Help is much appreciated.

You already answered you own question. Your connection URL (jdbc:mysql://localhost/game1) specifies the database (game1) to connect to, but that database does not exist. If you look at your Exception output is is probably telling to exactly that. Your app should NOT be creating the database. It should just be connecting to it and modifying it. You can try to set the URL to not include the database name and then just use the MySQL USE command to specify a database but that is a lot of un-nessasary work. Just do not have the app create it's database.

maybe you could try declaring your port and host separately as strings like the following and create the database then you should be okay.
`import java.sql.*;
public class Test {
public static void main(String args[]) {
Connection con;
try {
**String server = "localhost";
String port = "50000";** //generic port for DB2 jdbc
String url = "jdbc:db2://"+server+":"+port+"/sample"; String userid = ”userid";
String password = ”password";`

JDBC update using prepared statement

I am trying to update a table using Java JDBC. The method I am using does not throw any errors but the table is not updating. The create table method is below:
public static void Table()
{
Connection c = null;
Statement stmt = null;
try {
Class.forName("org.sqlite.JDBC");
c = DriverManager.getConnection("jdbc:sqlite:WalkerTechCars.db");
System.out.println("Opened database successfully");
stmt = c.createStatement();
String sql = "CREATE TABLE IF NOT EXISTS CUSTOMERS2 " +
"(PHONE TEXT PRIMARY KEY NOT NULL," +
" SURNAME TEXT NOT NULL, " +
" FIRSTNAME TEXT NOT NULL, " +
" HOME TEXT, " +
" ADDRESS TEXT, " +
" POSTCODE Text)";
stmt.executeUpdate(sql);
stmt.close();
c.close();
} catch ( Exception e ) {
System.err.println( e.getClass().getName() + ": " + e.getMessage() );
System.exit(0);
}
System.out.println("Customers2 created successfully");
}
The update method is below:
public static void updateCustomers()
{
Connection c = null;
PreparedStatement pstmt = null;
try {
Class.forName("org.sqlite.JDBC");
c = DriverManager.getConnection("jdbc:sqlite:WalkerTechCars.db");
c.setAutoCommit(false);
System.out.println("Opened database successfully");
String query = "UPDATE CUSTOMERS2 set ADDRESS = ? where PHONE = ? ";
pstmt = c.prepareStatement(query); // create a statement
pstmt.setString(1, "1"); // set input parameter 1
pstmt.setString(2, "DOES THIS WORK"); // set input parameter 2
pstmt.executeUpdate(); // execute update statement
pstmt.close();
c.close();
} catch ( Exception e ) {
System.err.println( e.getClass().getName() + ": " + e.getMessage() );
System.exit(0);
}
System.out.println("Update Completed successfully HELLO");
}
I have tried to find some clear instructions on this but cant find any. I do not really understand JDBC and prepared statement very well

When autoCommit is false (c.setAutoCommit(false);), you must manually commit the transaction...
Add...
c.commit()
After pstmt.executeUpdate();
You code also has a flaw, in that if some kind of error occurs during the preparation or execution of the statement, both the Connection and PreparedStatement could be left open, causing a resource leak
If you're using Java 7+ you can use the try-with-resources feature, for example...
try {
Class.forName("org.sqlite.JDBC");
try (Connection c = DriverManager.getConnection("jdbc:sqlite:WalkerTechCars.db")) {
c.setAutoCommit(false);
System.out.println("Opened database successfully");
String query = "UPDATE CUSTOMERS2 set ADDRESS = ? where PHONE = ? ";
try (PreparedStatement pstmt = c.prepareStatement(query)) {
pstmt.setString(1, "1"); // set input parameter 1
pstmt.setString(2, "DOES THIS WORK"); // set input parameter 2
pstmt.executeUpdate(); // execute update statement
c.commit();
}
} catch (SQLException exp) {
exp.printStackTrace();
}
} catch (ClassNotFoundException exp) {
exp.printStackTrace();
System.out.println("Failed to load driver");
}
This will ensure that regardless of how you leave the try block the resource will be closed.
You might also consider taking a look at the JDBC(TM) Database Access

Your update method will set ADDRESS to 1 if there is any row in table with PHONE = does this work.
Try to put Address in 1st Input parameter and Phone 2nd Input parameter

When a connection is created, it is in auto-commit mode.
We need to use [setAutoCommit] method only when we need to make Auto Commit false and make it manual commit after executing the query.
More details at Oracle site on JDBC Transaction.

Java SQL (JDBC) : how to move to the next column?

I'm trying to check if the "Username" and "Email" arguments in my constructor are existed in the SQL Table.
this is my code:
public DB(String usr, String eml, String pwd) {
this.usr = usr;
this.eml = eml;
this.pwd = pwd;
String jdbcUrl = "jdbc:mysql://localhost:3306/registered";
String jdbcUser = "....";
String jdbcPassword = "....";
try {
Class.forName("com.mysql.jdbc.Driver");
connection = DriverManager.getConnection(jdbcUrl, jdbcUser,
jdbcPassword);
statement = connection.createStatement();
now , if i use SELECT with two columns, like this:
String command = "SELECT UserName,Email FROM users WHERE UserName LIKE '" + this.usr.toString() + "';";
resultSet = statement.executeQuery(command);
and then do my loop for resultSet... like this:
while (resultSet.next()) {
if (usr.equalsIgnoreCase(resultSet.getString("UserName"))) {
System.out.println("UserName : " + this.usr + " is taken!");
}
else if (eml.equalsIgnoreCase(resultSet.getString("Email"))) {
System.out.println("Email : " + this.eml + " is taken!");
}
else {
System.out.println("Email : " + this.eml + " and UserName : " + this.usr + " are AVAILABLE!");
command = "INSERT users SET UserName = '" + this.usr.toString() + "',Email = '" + this.eml.toString() + "',Password = '" + this.pwd.toString() + "',Status = '0' ,Connected = '1';";
statement.executeUpdate(command);
}
}
} catch (SQLException e) {
System.out.println("SQLException: " + e.getMessage());
System.out.println("Vendor error: " + e.getErrorCode());
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
the
resultSet.next()
only runs over the "FIRST" column which means
if the "usr" exists in the table it works,
but if the "usr" does not exist in the table, the other two if statements does-not work ..
,... i want to check both first column and second,.. and maybe third or more soon.. , any help?

Your WHERE clause only tests for the UserName, so if the UserName doesn't match this.usr.toString(), the resultSet will be empty, so the while loop won't be entered.
You should change the query to match all the fields you care about - something like - "SELECT UserName,Email FROM users WHERE UserName = ... OR Email = ..."
If the resultSet is empty, you'll know that you can insert the new record. Otherwise, you can check which of the fields (UserName, Email) is already taken.
One more thing you should be aware of - executing a SQL statement without PreparedStatement makes your code vulnerable to SQL injection attacks.
You should change your code to something like this :
PreparedStatement pstmt = con.prepareStatement("SELECT UserName,Email FROM users WHERE UserName = ? OR Email = ?");
pstmt.setString(1, this.usr);
pstmt.setString(2, this.eml);
resultSet = pstmt.executeQuery();
You should change your INSERT statement similarly to use PreparedStatement.