Develop Reference

How to setup a SQL Server instance on my localhost?

I am exploring ways to connect to a SQL database using JDBC in Java and interact with it. Problem is no matter how I follow the syntax to make such connection it does not let me to connect to that instance of SQL Server on my laptop. I have seen other people being able to run such instances on their localhost instead and be able to connect to it via JDBS but I could not find any walkthroughs as how I can do the same. Any help with it will be greatly appreciated. Here is the connection I have on my laptop:
And here the JDBC connection URL that I try to make based on this on my code:
package helpers;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class DbHandler {
private static final String connectionUrl = "jdbc:sqlserver://LAPTOP-KAQ3H6IG//SQLEXPRESS:1433;database=pub;user=MyUserName;password=MyPassword";
public static void addNewJobWithName(String jobName) {
try (Connection connect = DriverManager.getConnection(connectionUrl)) {
connect.createStatement().execute("INSERT INTO [pub].[dbo].[jobs] (job_id, job_desc, min_lvl, max_lvl) VALUES (2,'QA3', 50, 100);");
} catch (SQLException e) {
e.printStackTrace();
}
}
}
And the error I receive:
The TCP/IP connection to the host LAPTOP-KAQ3H6IG//SQLEXPRESS, port 1433 has failed. Error: "LAPTOP-KAQ3H6IG//SQLEXPRESS. Verify the connection properties. Make sure that an instance of SQL Server is running on the host and accepting TCP/IP connections at the port. Make sure that TCP connections to the port are not blocked by a firewall.". at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(SQLServerException.java:237)
Thanks in advance for your help

Did a combination of things based on the comments made here and some other posts I read on stack overflow regarding other things to do to fully solve this problem here are the things that I did:
Changed my connection URL string to this:
"jdbc:sqlserver://localhost:1433;database=pub;user=MyUserName;password=MyPassword;encrypt=true;trustServerCertificate=true";
On SQL Server configuration manager clicked on 'SQL Server Network Configuration' and enabled 'Named Pipes' and 'TCP/IP' in 'Protocols for SQLEXPRESS' (where my local MSSQL instance is setup).
Clicking on TCP/IP in the same window, switched to the IP Address tab and entered '1433' as the port number for the IPAII section right at the end of the list (Leave the other port sections empty).
Restarted SQL Server (SQLEXPRESS) from the list of services in Windows.
Hope it can help other people having the same problem as well.

PGJDBC: could not receive data from client:

Dear StackOverFlowers,
I was trying event-driven LISTENER/NOTIFY on Postgres 9.6 (Windows 10).
I followed PGJDBC example given by Steve Taylor at https://www.openmakesoftware.com/postgresql-listen-notify-events-example/.
I started by downloading pgjdbc-ng-0.7-complete.jar and have put that in my CLASSPATH replacing standard JDBC driver.
When I am trying to connect to Postgres database using pgjdbc driver, I am getting an error:
connection received: host=127.0.0.1 port=50325
connection authorized: user=postgres database=scott
could not receive data from client: An existing connection was forcibly closed by the remote host.
Here are my system variables:
DBHost: localhost
DBName: scott
DBPort: 5432
DBUserName: postgres
DBPassword: postgres
I am not getting past the first hurdle, rest looks like Mount Everest. Please help me. Should you be needing the code, I am following Steve's code ditto.
Further to Joseph Larson's answer, the database is always running. I have connected to Postgres database from PGADMIN and Java successfully. I think issue is with the connect string. From Java when I am using standard JDBC which is provided by Postgres I am using URL like jdbc:postgresql://localhost:5432/dbname but PGJDBC suggests a different connect string like JDBC:PGSQL://localhost:5432/dbname. I tried to connect with that string (forcibly), it did not work. There is no method in PGJDBC PGDataSource for providing URL directly. I had to go through:
dataSource.setHost(DBHost);
dataSource.setPort(5432);
dataSource.setDatabase(DBName);
dataSource.setUser(DBUserName);
dataSource.setPassword(DBPassword);
And what URL it is sending to Database I am not able to figure out. Please suggest me a connect string and this problem is solved.
thanks
Thanks very much for asking me to post error messages:
Exception in thread "main" java.lang.NullPointerException
at com.impossibl.postgres.system.BasicContext.loadLocale(BasicContext.java:294)
at com.impossibl.postgres.system.BasicContext.init(BasicContext.java:273)
at com.impossibl.postgres.jdbc.PGConnectionImpl.init(PGConnectionImpl.java:251)
at com.impossibl.postgres.jdbc.ConnectionUtil.createConnection(ConnectionUtil.java:182)
at com.impossibl.postgres.jdbc.AbstractDataSource.createConnection(AbstractDataSource.java:723)
at com.impossibl.postgres.jdbc.PGDataSource.getConnection(PGDataSource.java:66)
at com.impossibl.postgres.jdbc.PGDataSource.getConnection(PGDataSource.java:58)
at PGListenNotify.<init>(PGListenNotify.java:26)
at PGListenNotify.main(PGListenNotify.java:37)
Here is source code:
import java.sql.SQLException;
import java.sql.Statement;
import com.impossibl.postgres.api.jdbc.PGConnection;
import com.impossibl.postgres.jdbc.PGDataSource;
public class PGListenNotify
{
PGConnection connection;
public PGListenNotify()
{
String DBHost = System.getenv("DBHost");
String DBName = System.getenv("DBName");
String DBUserName = System.getenv("DBUserName");
String DBPassword = System.getenv("DBPassword");
try
{
PGDataSource dataSource = new PGDataSource();
dataSource.setHost(DBHost);
dataSource.setPort(5432);
dataSource.setDatabase(DBName);
dataSource.setUser(DBUserName);
dataSource.setPassword(DBPassword);
connection = (PGConnection) dataSource.getConnection();
Statement statement = connection.createStatement();
}
catch (SQLException e)
{
e.printStackTrace();
}
}
public static void main(String[] args)
{
PGListenNotify ln = new PGListenNotify();
}
}

This looks like the Windows locale bug in pgjbdc-ng. It has been addressed, try the latest version 0.8.1.
The latest releases have detailed documentation related to asynchronous notifications here.
If it still fails to execute on your Windows system, please create an issue here.

Did you actually start a database server? I didn't know PostgreSQL server could run on Windows, but I've never tried.
I would simplify your problem a little. I know nothing about psql on Windows, but on Mac, I would start the server and then use the psql command (it's part of PostgreSQL) to ensure the server was up and running.
If you're to connecting, then the problems can be:
-There is no server at all
-The server isn't running on the port you're attempting
-The server isn't listening for connections on host 127.0.0.1 but could be listening on the actual IP address of your machine
-I'm not sure about that particular error, but username, password, or database may not exist.
I'd use psql to figure out which of those possible reasons is the real problem. That isolates out your program as being part of the problem, and it becomes entirely one of managing your database server.

is it possible to connect java application to online database

hello i am trying to connect my application to online database using the following code
import javax.swing.*;
import java.sql.*;
public class javacon {
Connection con = null;
private static final String url ="jdbc:mysql:\\sql204.byethost9.com:3306\\";
private static final String dbName = "b9_16134488_db";
private static final String userName = "b9_16134488";
private static final String password = "123.321";
public static Connection connectDB(){
try{
Class.forName("com.mysql.jdbc.Driver");
Connection con =DriverManager.getConnection("jdbc:mysql://sql204.byethost9.com:3306/b9_16134488_db/",userName,password);
JOptionPane.showMessageDialog(null, "connection is succseful");
return con;
}catch(Exception e){
JOptionPane.showMessageDialog(null, e);
return null;
}
}
}
but i am getting error says the driver has not received any packet
from the server
i found one answer this one says i have to go to my cpanel in my host and add my ip address there but i need every user to be connect to the database to login and logout

Mysql database has file my.cnf where bind-address might be specified. If that is not there, then mysql bind itself to all interfaces, otherwise only to specified one. More about this Bind-address
Also I guess user must have permissions to connect to database. 'user'#'ipaddress'. And more you can read here Connection access

Your code seems fine, your problem probably is related with your MySQL database not allowing connections from your host. The easiest way to find if this is the problem is trying to connect to the database from the same machine with the same credentials with MySQL Workbench.
There are three main things that can block your MySQL from receiving external connections:
1) Configuration
Edit my.cnf removing the following line:
bind-address = 127.0.0.1
2) User Host
In MySQL all users have defined from which host the connection can home from. 'user'#'%' would allow you to connect from any host.
3) Firewall
Make sure that the port 3306 is open.

Connecting to MySQL Server JDBC

I am trying to connect to a MySQL Server using JDBC tool in java (using eclipse). I was just wondering how to enter 2 user/password combinations. The first one is the one I use to connect to the server(for example when I ssh into the server) and the second one I enter into phpmyadmin. As of now, I am putting in the phpmyadmin password only into the jdbc connection properties and it's not connecting. This is my current statement:
conn = DriverManager.getConnection("jdbc:mysql://[IP of server]:3306/[Database Table name]", "[UserName (same as phpmyadmin)]","[Password (same as phpmyadmin)]");
I am getting a
java.sql.SQLException: null, message from server: "Host '[My computer's full host name]' is not allowed to connect to this MySQL server"
I was just wondering if I needed to enter my server login/password (the one I use for ssh) as well in addition to the phpmyadmin username/pwd. I am new to JDBC and MySQL server, so I would appreciate any tips.
Just for background, I am able to connect successfully through ssh and I can login to the server through phpmyadmin.

Here's how you can create an account that can access your server from another client machine:
CREATE USER 'bobby'#'localhost' IDENTIFIED BY 'some_password';
That creates the user, and says he can connect from localhost.
If he is on the machine 192.168.0.5, you'd do something like this:
CREATE USER 'bobby'#'192.168.0.5' IDENTIFIED BY 'some_password';
Then of course, you have to grant privileges appropriately:
GRANT ALL PRIVILEGES ON databasename.* TO 'bobby'#'localhost' WITH GRANT OPTION;
GRANT ALL PRIVILEGES ON databasename.* TO 'bobby'#'192.168.0.5' WITH GRANT OPTION;
That's been my experience anyway.
You're probably better off reading this section on how to specify MySQL accounts.

When you log in from PHPMyAdmin, the web server is located on the same server that hosts the Mysql database (in your case). Mysql, by default, does not allow connections from remote hosts; only the local machine may access the database.
I'll take a shot in the dark and say that the computer you're running the java code on is not the same machine that is hosting the mysql server. You must configure Mysql to allow connections from remote hosts via the config file and then change the Host row of the mysql.users table for the specified user to allow connection from your IP address (or, if security isn't your concern, any IP address.)
To configure mysql to allow connections from remote hosts you must remove the "bind-address=" line from the configuration file.
To allow any host to log on to a specific mysql user, you must set the mysql.users Host` column to "%".
Both of these must be done.

public class MysqlConnect{
public static void main(String[] args) {
System.out.println("MySQL Connect Example.");
Connection conn = null;
String url = "jdbc:mysql://localhost:3306/";
String dbName = "jdbctutorial";
String driver = "com.mysql.jdbc.Driver";
String userName = "root";
String password = "root";
try {
Class.forName(driver).newInstance();
conn = DriverManager.getConnection(url+dbName,userName,password);
System.out.println("Connected to the database");
conn.close();
System.out.println("Disconnected from database");
} catch (Exception e) {
e.printStackTrace();
}
}
}

Having trouble connecting to mySQL server on linux server from netbeans/java

I am unable to connect to a MySQL server which is hosted on a linux server through netbeans.
All of these credentials work when connecting through MySQL Workbench "Standard TCP/IP through ssh".
Here is my code:
public class Database {
private static final String DRIVER = "com.mysql.jdbc.Driver";
private static final String URL = "jdbc:mysql://john.myschool.edu:3306/cs3610";
private static final String USERNAME = "mbrooke";
private static final String PASSWORD = "mypass";
private Connection connection;
public Database() throws Exception{
try{
connect();
}catch(SQLException e){
if(connection !=null){
connection.close();
}
}
}
//Open connection to database
private void connect() throws Exception{
connection = null;
Class.forName (DRIVER).newInstance ();
connection = DriverManager.getConnection(URL,USERNAME,PASSWORD);
}
}
I am getting SQLException with #521 on the line that starts "connection = DriverManager..." and I'm not sure what is causing this problem. The driver seems to be installed correctly as, when stepping through, I make it past the "Class.forName(D..." line with no exceptions thrown.

It sounds like your Database server doesn't have port 3306 open, or your MySQL credentials aren't allowed to use remote connections.
MySQL Workbench's TCP/IP over SSH setting first opens an SSH connection to the SSH server, then connects to the database server (often localhost or 127.0.0.1). So the MySQL connection is actually initiated from the SSH server. So the ability to connect through that channel only demonstrates that your java code would work if it were running on the server into which you're SSHing. But you may still have a firewall or MySQL permissions issue when trying to run the code from another machine.
I would try downloading a MySQL client to your machine and seeing if you can connect using that method: mysql -h myDatabaseServer.school.edu cs3610 -u mbrooke -p'mypass' and see if that works. You'll likely either get a "connection not available" error or a "user mbrooke doesn't have permission to access remotely" which should give you some insight into which problem you're facing.

Try it without ending slash
URL = "jdbc:mysql://john.myschool.edu:3306/cs3610/";
like
URL = "jdbc:mysql://john.myschool.edu:3306/cs3610";
or you have a Database named "cs3610/"