How to Connect to MySql

Connect to a MySql Server

Connecting to MySql require entering the MySql host, port, database user and password as explained in the Connection Dialog page.

If you fail connecting you may need to check one of the items below.

1. Start MySql ServiceTo make sure MySql is up and running
2. MySql User Names MySql users are a combination of username and the host names allowed to connect.
3. Enable Remote Connections to be able to connect from another computer.
4. Reset Password or Missing Privileges to Login fix the missing login privileges or forgotten password.
5. Allow MySql through Windows Firewall Firewalls may block the connections.
6. What to Check on the Common Error Messages a list of error messages and how to fix them.
7. Run MySql using Docker Container
8. Guided MySql Installation on Windows

Introduction

Most of the commands in this article can be executed from MySql Command Line console. Start the console like this:

1. Open the command prompt by following this steps: Start -> run -> cmd -> press enter.
2. Navigate to your MySql installation folder (Default: C:\Program Files\MySql\MySql Server 12\bin)
3. Type in: mysql -u root -p

MySql users are a combination of username and host name allowed to connect ( can be '%' for any host). Check the current users and hosts allowed to connect, execute this from the mysql command prompt:

SELECT User, Host FROM mysql.user
+------+------------+
| User | Host       |
+------+------------+
| root | localhost  |
| user | %          |
+------+------------+
        

Localhost means it can connect only from the same computer, while % means it can connect from any computer. If MySql runs in a docker container the hosts are different ( like running on another computer ).

Enable MySql Service

If MySql service is not running, you won't be able to connect.

Windows
To enable MySql Service follow this steps:

1. Go to Start -> Control Panel -> System and Security -> Administrative Tools -> Component Services
   
   
2. Open Service Local
3. Find your MySql service name setup during installation (For Example: MySql56)
4. Right click on the service name and click start.
   
   

Linux
To start the MySql service on linux just type in the console: service mysqld start

Enable Remote Connectivity

Enabling remote connections require to enable TCP/IP connections in the configuration, and create a user allowed to connect from any host.

Enable TCP/IP Connectivity From Remote Hosts

To enable MySql to listen to remote connections, you need to edit your defaults file, located in DATADIR\my.ini (Windows) or /etc/my.cnf (Linux). Edit this configuration file and comment out the skip-networking line ( if any ) and set bind-address like this:

#skip-networking
bind-address = ::

Next, restart MySql service using

sudo /etc/init.d/mysql restart

Create a User Allowed to Connect from Remote Hosts

Check first which users are allowed to connect and from which hosts, using the query

SELECT User, Host FROM mysql.user

Create a new user allowed to connect from any hosts. Use '%' for any host or use a specific host IP.

CREATE USER 'dbschema'@'%' IDENTIFIED BY 'password';
GRANT ALL PRIVILEGES ON *.* TO 'sample'@'%';
FLUSH PRIVILEGES;

By default MySql already has an user 'root'@'localhost', with a password you should have already set during installation. This will work only for connections from the same machine. Docker containers are like different machines. Connecting from DbSchema you should use a different user, like 'dbschema', with % for all hosts or the specific host IP.

Grant Privileges on Specific Tables

GRANT ALL PRIVILEGES ON *.* TO 'USERNAME'@'IP' IDENTIFIED BY 'PASSWORD';
FLUSH PRIVILEGES;
quit

The privileges can be allowed on a specifc table using <DatabaseName>.<TableName>

Reset Password or Missing Privileges to Login

If you forgot the database user password you can follow this steps and reset it :

Windows

1. Shut down MySql or MySql service: Go to Start -> run -> services.msc -> MySQL -> right click and select STOP
2. Create a text file reset.txt. Im my case I save it under "C:\Temp\reset.txt". In this file paste the following lines:

   UPDATE mysql.user SET Password=PASSWORD('EnterPassword') WHERE User='root';
   FLUSH PRIVILEGES;
   

   Replace "EnterPassword" with your new password. Also make sure that the UPDATE and FLUSH commands are on separate lines!
   
   
3. Open the command prompt and navigate to your MySQL or MySql bin directory inside the program folder ("C:\Program Files\MySQL\MySQL Server 5.0\bin" or "C:\Program Files\MySql\bin")
   enter the following command

   mysqld.exe --init-file=C:\Temp\reset.txt --console
   

   This will replace your root password with the one you have set in the text file. The command may hang as the daemon continues to run. You can stop it ( Ctrl-C ) and start MySql again from Windows Services.
4. Restart MySQL Service: Start -> run -> services.msc -> MySQL > right click and select START
   

Linux

1. Log in as root and stop MySql service(daemon) by entering the command: service mysql stop
2. Start MySql service(daemon) and skip the grant tables which store the passwords by entering the command: mysqld_safe --skip-grant-tables
3. Now you should be able to connect to MySql without a password.Run the following commands:

   mysql --user=root mysql
   

   update user set Password=PASSWORD('new-password') where user='root';
   flush privileges;
   exit
   

4. Log in as root and start the MySql daemon by entering the command: service mysqld start

Enable Connections to Database through Windows Firewall

The common reason for connectivity problems is the error 'Communications link failure'. This is because during the MySql installation the checkbox to add an firewall exception was not enabled. To enable it later do as follow :

• Open Windows Firewall by clicking the Start button Picture of the Start button, and then clicking Control Panel. In the search box, type firewall, and then click Windows Firewall.
  
• In the left pane, click Advanced settings. Administrator permission required If you're prompted for an administrator password or confirmation, type the password or provide confirmation.
  
• In the Windows Firewall with Advanced Security dialog box, in the left pane, click Inbound Rules, and then, in the right pane, click New Rule.
  
• Follow the instructions in the New Inbound Rule wizard. Make sure to select Add Port.
  
• For the Port name use MySql.
  
• For the specific local port use 3306
  
• Make sure to check off Allow the Connection
  
• For When does this rule apply?
  
• Put a check in Domain, private, and public.
  
• Make sure to follow the directions above for creating an Outbound rule...basically the same way except you click Outbound Rules on the left pane.
  

SSL Connections

If you wish to use ssl encryption, append this '?useSSL=true&verifyServerCertificate=false' to the URL Pattern in the JDBC Driver Manager.

Common Error Messages

Exception: Communications link failure. Exception: Communications link failure. The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

1. Check if the MySql Service on Server is Started
   
   
2. Check the MySql server port and hostname
   Test the connection using the PING button from the Connection Dialog.
   The default MySql port is 3306. However, this port can be changed for each MySql instance.
   Check the server files my.ini or my.cnf, in the mysqld section, to see the configured port, for example, port=3306.
   Find out the computer name right clicking My Computer and selecting Properties
   
   
3. Disable Firewalls on Server and Client
   Firewalls on client or server may block the connections. Configure them to accept incoming connections for MySql port or disable them.
   
   
4. Check the JDBC Driver Version
   DbSchema includes one JDBC driver for MySql. If the driver is not an actual version,
   search the internet for 'download MySql driver' or look on http://dev.mysql.com/downloads/connector/j/
   You will probably download a file MySql-connector-java-x.x.x.zip.
   Decompress it and look for a file MySql-connector-java-x.x.x.jar. Upload this file in the in DbSchema JDBC Driver Manager.
   
   

• Exception: Test Connection Failed java.sql.SQLException: null, message from server: "Host 'YOUR_IP' is not allowed to connect to this MySql server"
Your ip is not allowed to connect to the MySql server.
• If the bind_address values is set to 127.0.0.1 in the MySql configuration file, the MySql server will not accept connections from remote hosts.
  The bind_address line in the MySql configuration file (my.ini or my.cnf) can either be removed or commented out to allow remote connections.

SSL Connections

If you wish to use ssl encryption, append this '?useSSL=true&verifyServerCertificate=false' to the URL Pattern in the JDBC Driver Manager.

Common Error Messages

Exception: Communications link failure.The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

1. 1Check if the MySQL Service on Server is Started
   
   
2. 2Check the MySQL server port and hostname
   Test the connection using the PING button from the Connection Dialog.
   The default MySql port is 3306. However, this port can be changed for each MySQL instance.
   Check the server files my.ini or my.cnf, in the mysqld section, to see the configured port, for example, port=3306.
   Find out the computer name right clicking My Computer and selecting Properties
   
   
3. 3Disable Firewalls on Server and Client
   Firewalls on client or server may block the connections. Configure them to accept incoming connections for MySql port or disable them.
   
   
4. 4Check the JDBC Driver Version
   DbSchema includes one JDBC driver for MySql. If the driver is not an actual version,
   search the internet for 'download mysql driver' or look on http://dev.mysql.com/downloads/connector/j/
   You will probably download a file mysql-connector-java-x.x.x.zip.
   Decompress it and look for a file mysql-connector-java-x.x.x.jar. Upload this file in the in DbSchema JDBC Driver Manager.
   
   

Exception: Test Connection Failed java.sql.SQLException: null, message from server: "Host 'YOUR_IP' is not allowed to connect to this MySQL server" Your ip is not allowed to connect to the mysql server.

1. 1 If the bind_address values is set to 127.0.0.1 in the MySQL configuration file, the MySQL server will not accept connections from remote hosts.
   The bind_address line in the MySQL configuration file (my.ini or my.cnf) can either be removed or commented out to allow remote connections.

Run MySql as Docker Container

A short intro can be found here. Install docker then run from docker prompt:

docker pull mysql/mysql-server:8.0
docker run --name=mysql -p 3306:3306 -e MYSQL_ROOT_PASSWORD=123456 -d mysql/mysql-server:8.0

To get a MySql prompt:

docker exec -it mysql mysql -uroot -p

Now you can create further users in the database:

CREATE USER 'john'@'%' IDENTIFIED BY 'john';
GRANT ALL privileges ON *.* TO 'john'@'%';
FLUSH PRIVILEGES;

To drop the container:

docker stop mysql
docker rm mysql
docker system prune

Guided MySql Installation on Windows

Download MySql from http://dev.mysql.com/downloads/

During the installation you have to enter the password for the database user root. Also you may want to enable access to MySql from remote computers

At this step set a firewall exception for MySql to allow remote computers to connect to MySql. The port number which is set here will be used also by DbSchema.

At this step you enter the root password and enable access to MySql database from remote computers :

After installation you can enable MySql to write all its executed SQL statements to a log file. For this edit the Program Files/MySql/data/my.cfg and add log=<file>

MySql Statements

• Create Database

  mysql -U root -p
  use <schema>;
  show tables;
  create database test;
  drop database test;

• Change Table Engine to Myisam

  ALTER TABLE schema.table ENGINE=Myisam;