TABLE OF CONTENTS (HIDE)

How to Install MySQL 5.6 (on Windows, Mac OS X, Ubuntu) and Get Started with SQL Programming

 

This article is currently applicable to MySQL 5.6. There are some changes in MySQL 5.7 (such as database initialization and password column), see "How to Install MySQL 5.7".

This practical can be completed in a 3-hour session.

Introduction to Relational Database and SQL

Relational Databases

A relational database organizes data in tables. A table has rows (or records) and columns (or fields). Tables are related based on common columns to eliminate data redundancy and ensure data integrity.

Popular Relationship Database Management System (RDBMS) includes the commercial Oracle, IBM DB2, Microsoft SQL Server and Access, SAP SyBase and Teradata; and the free MySQL, PostgreSQL, Embedded Apache Derby (Java DB), mSQL (mini SQL), SQLite and Apache OpenOffice's Base.

Structure Query Language (SQL)

A high-level language, called Structure Query Language (SQL), had been designed for structuring relational databases; and for Creating, Updating, Reading and Deleting (CURD) records. SQL defines a set of commands, such as SELECT, INSERT, UPDATE, DELETE, CREATE TABLE, DROP TABLE, and etc.

Edgar F. Codd (of IBM) proposed the Relational Database Model in 1970. SQL, one of the earlier programming language, was subsequently developed by Donald D. Chamberlin and Raymond F. Boyce at IBM in the early 1970s. Oracle, subsequently, took it to a new height.

ANSI (American National Standard Institute) established the first SQL standard in 1986 (SQL-86 or SQL-87) - adopted by ISO/IEC as "ISO/IEC 9075" - followed in 1989 (SQL-89), 1992 (SQL-92 or SQL2), 1999 (SQL-99 or SQL3), 2003 (SQL-2003), 2006 (SQL-2006) and 2011 (SQL-2011). However, most of the database vendors have their own directs, e.g., PL/SQL (Oracle), Transact-SQL (Microsoft, SAP), PL/pgSQL (PostgreSQL).

SQL By Examples

A relational database system contains many databases (or schemas). A database comprises one or more tables. A table have rows (or records) and columns (or fields).

Suppose we have created a table called class101, in a database called studentdb, with 3 columns: id, name and gpa. A column has a data type. We choose: INT (integer) for column id, FLOAT (floating-point number) for gpa, and VARCHAR(50) (variable-length string of up to 50 characters) for name. There are 4 rows in the table as follows:

Database: studentdb
Table: class101
+-----------+--------------------+-------------+
| id (INT)  | name (VARCHAR(50)) | gpa (FLOAT) |
+-----------+--------------------+-------------+
|   1001    | Tan Ah Teck        |  4.5        |
|   1002    | Mohammed Ali       |  4.8        |
|   1003    | Kumar              |  4.8        |
|   1004    | Kevin Jones        |  4.6        |
+-----------+--------------------+-------------+

SQL provides an easy and intuitive way to interact with relational databases.

SELECT
-- SYNTAX
SELECT column1, column2, ... FROM tableName WHERE criteria
SELECT * FROM tableName WHERE criteria
 
-- EXAMPLES
SELECT name, gpa FROM class101
   -- Select columns name and gpa from table class101.
   +--------------+------+
   | name         | gpa  |
   +--------------+------+
   | Tan Ah Teck  |  4.5 |
   | Mohammed Ali |  4.8 |
   | Kumar        |  4.8 |
   | Kevin Jones  |  4.6 |
   +--------------+------+
 
SELECT * FROM class101
   -- Select ALL columns from table class101.
   -- The wildcard * denotes all the columns.
   +------+--------------+------+
   | id   | name         | gpa  |
   +------+--------------+------+
   | 1001 | Tan Ah Teck  |  4.5 |
   | 1002 | Mohammed Ali |  4.8 |
   | 1003 | Kumar        |  4.8 |
   | 1004 | Kevin Jones  |  4.6 |
   +------+--------------+------+
 
SELECT name, gpa FROM class101 WHERE gpa >= 4.7
   -- Select columns name and gpa, where the rows meet the criteria.
   -- You can compare numbers using =, >, <, >=, <=, <> (!=)
   +--------------+------+
   | name         | gpa  |
   +--------------+------+
   | Mohammed Ali |  4.8 |
   | Kumar        |  4.8 |
   +--------------+------+
    
SELECT name, gpa FROM class101 WHERE name = 'Tan Ah Teck'
   -- Full-match (= or !=) on string. Strings are enclosed in single quotes.
   +-------------+------+
   | name        | gpa  |
   +-------------+------+
   | Tan Ah Teck |  4.5 |
   +-------------+------+
 
SELECT name FROM class101 WHERE name LIKE 'k%'
   -- Use "LIKE" for string pattern-matching, with
   --   wildcard % matches zero or more (any) characters;
   --   wildcard _ matches one (any) character.
   +-------------+
   | name        |
   +-------------+
   | Kumar       |
   | Kevin Jones |
   +-------------+
 
SELECT * FROM class101 WHERE gpa > 4 AND name LIKE 'k%' ORDER BY gpa DESC, name ASC
   -- Use AND, OR, NOT to combine simple conditions.
   -- Order the results in DESC (descending) or ASC (Ascending)
   +------+-------------+------+
   | id   | name        | gpa  |
   +------+-------------+------+
   | 1003 | Kumar       |  4.8 |
   | 1004 | Kevin Jones |  4.6 |
   +------+-------------+------+
DELETE
-- SYNTAX
DELETE FROM tableName WHERE criteria
 
-- EXAMPLES
DELETE FROM class101
  -- Delete ALL rows from the table class101! Beware that there is NO UNDO!
DELETE FROM class101 WHERE id = 33
  -- Delete rows that meet the criteria.
INSERT
-- SYNTAX
INSERT INTO tableName VALUES (firstColumnValue, ..., lastColumnValue)       -- All columns
INSERT INTO tableName (column1, column2, ...) VALUES (value1, value2, ...)  -- Selected Columns
 
-- Example
INSERT INTO class101 VALUES (1001, 'Tan Ah Teck', 4.5)
  -- List value of all columns.
INSERT INTO class101 (name, gpa) VALUES ('Peter Jones', 4.55)
  -- Missing fields will be set to their default values or NULL
UPDATE
-- SYNTAX
UPDATE tableName SET column = value WHERE criteria
 
-- EXAMPLES
UPDATE class101 SET gpa = 5.0                                  -- ALL rows
UPDATE class101 SET gpa = gpa + 1.0 WHERE name = 'Tan Ah Teck' -- Selected rows
CREATE TABLE
-- SYNTAX
CREATE TABLE tableName (column1Name column1Type, column2Name column2Type, ...)
 
-- EXAMPLES
CREATE TABLE class101 (id INT, name VARCHAR(50), gpa FLOAT)
DROP TABLE
-- SYNTAX
DROP TABLE tableName
 
-- EXAMPLES
DROP TABLE class101  -- Delete the table. Beware that there is No UNDO!!!
Notes:
  1. Case Sensitivity: SQL keywords, names (identifiers), strings may or may not be case-sensitive, depending on the implementation.
    • In MySQL, the keywords are NOT case-sensitive. For clarity, I show the keywords in uppercase in this article.
    • For programmers, it is BEST to treat the names (identifiers) and strings as case-sensitive.
      [In MySQL, column-names are always case insensitive; but table-names are case-sensitive in Unix, but case-insensitive in Windows (confused!!). Case-sensitivity in string comparison depends on the collating sequence used (?!).]
  2. Quotes for String: SQL strings are enclosed in single quotes, but most implementations (such as MySQL) also accept double quotes.

Introduction to MySQL Relational Database Management System (RDBMS)

SQL is a language for interacting with relational databases. On the other hand, MySQL is a system - a Relational Database Management System.

MySQL is the most used, and possibly the best industrial-strength, open-source and free Relational Database Management System (RDBMS). MySQL was developed by Michael "Monty" Widenius and David Axmark in 1995. It was owned by a Swedish company called MySQL AB, which was bought over by Sun Microsystems in 2008. Sun Microsystems was acquired by Oracle in 2010.

MySQL is successful, not only because it is free and open-source (there are many free and open-source databases, such as Apache Derby (Java DB), mSQL (mini SQL), SQLite, PostgreSQL and Apache OpenOffice's Base), but also for its speed, ease of use, reliability, performance, connectivity (full networking support), portability (run on most OSes, such as Unix, Windows, Mac), security (SSL support), small size, and rich features. MySQL supports all features expected in a high-performance relational database, such as transactions, foreign key, replication, subqueries, stored procedures, views and triggers.

MySQL is often deployed in a LAMP (Linux-Apache-MySQL-PHP), WAMP (Windows-Apache-MySQL-PHP), or MAMP (Mac-Apache-MySQL-PHP) environment. All components in LAMP is free and open-source, inclusive of the Operating System.

The mother site for MySQL is www.mysql.com. The ultimate reference for MySQL is the "MySQL Reference Manual", available at http://dev.mysql.com/doc. The reference manual is huge - the PDF has over 3700 pages!!!

image

MySQL operates as a client-server system over TCP/IP network. The server runs on a machine with an IP address, on a chosen TCP port number. The default TCP port number for MySQL is 3306, but you are free to choose another port number between 1024 and 65535. Users can access the server via a client program, connecting to the server at the given IP address and TCP port number.

A MySQL database server contains one or more databases (or schemas). A database contains one or more tables. A table consists of rows (or records) and columns (or fields).

How to Install MySQL and Get Started with Database Programming

I would like you to install MySQL on your own machine, because I want you to learn how to install, customize and operate complex industrial software system.

Step 1: Download and Install MySQL

For Windows

  1. Download MySQL ZIP ARCHIVE from http://dev.mysql.com/downloads/mysql/:
    1. Choose "General Available (GA) Releases" tab.
    2. In "Select Platform", choose "Microsoft Windows".
    3. In "Other Downloads", download the 32-bit or 64-bit ZIP ARCHIVE (mysql-5.6.{xx}-win32.zip or mysql-5.6.{xx}-winx64.zip, about 340MB).
      [You can check whether your Windows is 32-bit or 64-bit from "Control Panel" ⇒ System ⇒ System Type.]
    4. There is NO need to "Sign-up" - Just click "No thanks, just start my downloads!".
  2. UNZIP into a directory of your choice. DO NOT unzip into your desktop (because its path is hard to locate). I suggest that you create a directory "d:\myProject" (or "c:\myProject" if you do not have a D drive) and unzip into there. MySQL will be unzipped as "d:\myProject\mysql-5.6.{xx}-winx64".
    For ease of use, we shall shorten and rename the directory to "d:\myProject\mysql". Take note of the installed directory!!

I recommend using the "ZIP" version, instead of the "Windows Installer" version for academic learning. You can simply delete the entire MySQL directory when it is no longer needed (without running the un-installer). You are free to move or rename the directory. You can also install (unzip) multiple copies of MySQL in the same machine on different directories.

For Mac OS X

  1. Download the MySQL "DMG Archive" from http://dev.mysql.com/downloads/mysql/:
    1. Choose "General Available (GA) Releases" tab.
    2. In "Select Platform", choose the "Mac OS X".
    3. Select the appropriate "DMG Archive" for your specific Mac OS version: For example, for Lion (10.7) and Core i7 processor, choose "Mac OS X ver. 10.7 (x86, 64-bit), DMG Archive (117.5M)".
    4. There is NO need to "Sign-up" - Just click "No thanks, just start my download".
  2. To install MySQL:
    1. Go to "Downloads" ⇒ Double-click ".dmg" file downloaded.
    2. Double-click the "mysql-5.6.{xx}-osx10.x-xxx.pkg" ⇒ Follow the instructions to install MySQL. Click "continue" if "unindentified developer" warning dialog appears. (If double-click has no response, right-click ⇒ open with ⇒ installer.)
    3. MySQL will be installed in "/usr/local/mysql-5.6.{xx}-osx10.x-x86_xx" directory. A symbolic link "/usr/local/mysql" will be created automatically to the MySQL installed directory.
    4. Eject the ".dmg" file.

MySQL will be installed in /usr/local/mysql. Take note of this installed directory!!

For Ubuntu

Refer to "How to install MySQL 5 on Ubuntu".


I shall assume that MySQL is installed in directory "d:\myProject\mysql" (for Windows) or /usr/local/mysql (for Macs). But you need to TAKE NOTE OF YOUR MySQL INSTALLED DIRECTORY. Hereafter, I shall denote the MySQL installed directory as <MYSQL_HOME> in this article.

Step 2: Create the Configuration File

For Windows

Use a text editor (such as NotePad++ or TextPad) to create the following configuration file called "my.ini" and save it in YOUR MySQL INSTALLED DIRECTORY (e.g., "d:\myProject\mysql"). Lines beginning with # are comments.

# Save as "my.ini" in your MySQL installed directory (e.g. d:\myProject\mysql)
[mysqld]
# Run the server on this TCP port number
port=8888
   
[client]
# MySQL client connects to the server running on this TCP port number
port=8888

(For Notepad Users) Don't use Notepad for programming. But if you use Notepad, make sure that you double-quote the filename "my.ini" when saving the file; otherwise, it may be saved as "my.ini.txt". Worse still, you will not see the file extension ".txt" unless you enable displaying of file extension. Nonetheless, "my.ini.txt" has file-type description of "Text Document"; while "my.ini" has "Configuration Settings".
Don't use Notepad for programming!!! At the minimum, you should have Notepad++.

(Enabling Display of File Extension) Programmers need to view the file extension (such as .txt, .ini). To display the file extension, run "Control Panel" ⇒ "Folder Options" ⇒ Select tab "View" ⇒ Uncheck "Hide extensions for known file types".

(For Advanced Users Only) Where to place my.ini (or my.cnf) configuration file?
In Windows, the options are combined from the following files in this order: c:\Windows\my.ini, c:\Windows\my.cnf, c:\my.ini, c:\my.cnf, <MYSQL_HOME>\my.ini, <MYSQL_HOME>\my.cnf. If an option is specified in more than one places, the last setting takes effect. Our my.ini is kept in <MYSQL_HOME>, which overrides all the previous settings. Alternatively, you can keep the my.ini in any location, and use the startup option --defaults-file=filename to specify the location of the configuration file and bypass all the files listed above.

For Mac OS X

  1. The default TCP port number used by MySQL Server is 3306.
  2. For novices: SKIP THIS STEP to run the MySQL Server on port 3306. Goto Step 3 to start the server.
    For non-novices: You can change the port number by editing (e.g., via "sudo nano") the configuration file "my.cnf" at directory "/usr/local/mysql".
    [mysqld]
    port=8888
    
    [client]
    port=8888
    I consider you novices if you don't know how to edit this file!

(Advanced) On Unixes, the MySQL Server reads the options file in this order: "/etc/my.cnf", "/etc/mysql/my.cnf" ("SYSCONFDIR/mf.cnf"), "$MYSQL_HOME/my.cnf", "[DataDir]/my.cnf", "~/.my.cnf".

Explanation
  • [mysqld], [client]
    MySQL operates as a client-server system. It provides a server program and a client program. There are two sections in the configuration: [mysqld] for the server program, and [client] for the client program.
  • port=8888
    MySQL is a TCP/IP application. The default TCP port number for MySQL is 3306. You may choose any port number between 1024 to 65535, which is not used by an existing application. I choose 8888 for our server.
  • There are many more configuration options. Check the MySQL documentation.

Step 3: Start the Server

The MySQL is a client-server system. The database is run as a server application. Users access the database server via a client program, locally or remotely thru the net, as illustrated:

image
  1. The server program is called "mysqld" (with a suffix 'd', which stands for daemon - a daemon is a non-interactive process running in the background).
  2. The client program is called "mysql" (without the 'd').

The MySQL programs (mysqld and mysql) are kept in the "bin" sub-directory of the MySQL installed directory <MYSQL_HOME>.

Startup Server

For Windows

To start the database server, launch a CMD shell. Set the current directory to "<MYSQL_HOME>\bin", and run command "mysqld --console".

-- Change the current directory to MySQL's "bin" directory
-- Assume that the MySQL installed directory is "d:\myProject\mysql"
Prompt> d:                       -- Set the current drive
D:\...> cd \myProject\mysql\bin  -- Change Directory to the MySQL's bin directory
 
-- Start the MySQL Database Server
D:\myProject\mysql\bin> mysqld --console
......
......
XXXXXX XX:XX:XX [Note] mysqld: ready for connections.
Version: '5.6.xx-community'  socket: ''  port: 8888  MySQL Community Server (GPL)

Take note of the TCP port number.

For Mac OS X

MySQL is installed in /usr/local/mysql. Open a new "Terminal" and issue these commands to start the MySQL server:

-- Change the current directory to MySQL's "bin" directory
Prompt$ cd /usr/local/mysql/bin
 
-- Start the MySQL Database Server
Prompt$ sudo ./mysqld_safe --console
Enter your password: [type your computer password and enter. NOTHING will be shown for security.]
xxxxxx xx:xx:xx mysql_safe logging to '/usr/local/mysql/data/xxxxxx.err'
xxxxxx xx:xx:xx mysql_safe Starting mysqld daemon with databases from /usr/local/mysql/data
Alternatively, you can start/stop the MySQL server via graphical control. Click Apple Icon ⇒ System Preferences ⇒ MySQL ⇒ Start/Stop.

The MySQL database server is now started, and ready to handle clients' requests.

Notes:
  • The --console option directs the server output messages to the console. Without this option, you will see a blank screen.

Anything that can possibly go wrong, does! Read "Common Problems in Starting the MySQL Server after Installation".

Shutdown Server

For Windows

The quickest way to shut down the database server is to press Ctrl-C to initiate a normal shutdown. DO NOT KILL the server via the window's CLOSE button.

Observe these messages from the MySQL server console:

XXXXXX XX:XX:XX [Note] mysqld: Normal shutdown
......
XXXXXX XX:XX:XX  InnoDB: Starting shutdown...
XXXXXX XX:XX:XX  InnoDB: Shutdown completed; log sequence number 0 44233
......
XXXXXX XX:XX:XX [Note] mysqld: Shutdown complete

For Mac OS X

To shutdown the server, start a new Terminal and issue:

Prompt$ cd /usr/local/mysql/bin
 
Prompt$ sudo ./mysqladmin -u root -p shutdown
      // Hit "Enter" key when you are prompted for the password
Alternatively, you can start/stop the MySQL server via graphical control. Click Apple Icon ⇒ System Preferences ⇒ MySQL ⇒ Start/Stop.

WARNING: You should properly shutdown the MySQL server. Otherwise, you might corrupt the database and have problems restarting it.

BUT, you may kill the "mysqld" process in Task Manager (for Windows); or Activity Monitor (for Mac OS X); or System Monitor (for Ubuntu).

Step 4: Start a Client

Recall that the MySQL is a client-server system. Once the server is started, one or more clients can be connected to the database server. A client could be run on the same machine (local client); or from another machine (remote client) over the net.

To login to the MySQL server, you need to provide a username and password. During the installation, MySQL creates a superuser called "root" WITHOUT setting its password.

The MySQL installation provides a command-line client program called "mysql". (Recall that the server program is called "mysqld"; the clinet program does not have the suffix 'd')

Let's start a command-line client with superuser "root". First, make sure that the server is running (see previous step to re-start the server if it has been shutdown).

For Windows

Start a new CMD shell to run the client:

-- Change the current directory to <MYSQL_HOME>\bin.
-- Assume that the MySQL is installed in "d:\myProject\mysql".
Prompt> d:                       -- Change the current drive
D:\...> cd \myProject\mysql\bin  -- Change Directory to YOUR MySQL's "bin" directory
   
-- Start a client with superuser "root"
D:\myProject\mysql\bin> mysql -u root -p
Enter password:     // Hit "Enter" key for empty password set in installation 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.1.39-community MySQL Community Server (GPL)
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

-- Client started. The prompt changes to "mysql>".
-- You can now issue SQL commands.
mysql>

For Mac OS X

Open a new "Terminal" and issue these commands to start a MySQL client with superuser root:

-- Change the current directory to <MYSQL_HOME>\bin.
Prompt$ cd /usr/local/mysql/bin
 
-- Start a client with superuser "root"
Prompt$ ./mysql -u root -p
Enter password:     // Hit "Enter" key for empty password set in installation 
Welcome to the MySQL monitor.  Commands end with ; or \g.
......
-- Client started. The prompt changes to "mysql>".
-- You can now issue SQL commands.
mysql>

(Skip Unless...) Read "Common Problems in Starting the MySQL Client".

Before we proceed, let's issue a "status" command:

mysql> status
--------------
mysql  Ver 14.14 Distrib 5.1.51, for Win32 (ia32)
......
Current user:           root@localhost
TCP port:               8888    -- for Windows only
......

Step 5: Set the Password for Superuser "root" and Remove the Anonymous User

As mentioned earlier, the MySQL installation creats a superuser called "root" WITHOUT setting its password. "root" is a privileged user that can do anything, including deleting all the databases. Needless to say, you have to set a password for root. The root's password shall only be made available to the database administrator, not the regular users.

Set Password for "root"

Let's continue with our client session:

-- Query all the users and their passwords from database "mysql" table "user"
-- End the commands with a semi-colon (;)
mysql> select host, user, password from mysql.user;
+-----------+------+----------+
| host      | user | password |
+-----------+------+----------+
| localhost | root |          |
| 127.0.0.1 | root |          |
| ::1       | root |          |
| localhost |      |          |
+-----------+------+----------+
   
-- Set password for 'root'@'127.0.0.1'. Replace xxxx with your chosen password
-- (For my students: use xxxx as the password. Otherwise,
--   you will ask me what is your password next week.)
-- Take note that strings are to be enclosed by a pair of single-quotes.
mysql> set password for 'root'@'127.0.0.1'=password('xxxx');
Query OK, 0 rows affected (0.00 sec)
   
-- Set password for 'root'@'localhost'
mysql> set password for 'root'@'localhost'=password('xxxx');
Query OK, 0 rows affected (0.00 sec)
  
-- Set password for 'root'@'::1'
mysql> set password for 'root'@'::1'=password('xxxx');
Query OK, 0 rows affected (0.00 sec)
  
-- Query the users and passwords again.
-- Passwords are NOT stored in clear-text for security. Instead, a "hash" value of passwords are stored.
mysql> select host, user, password from mysql.user;
+-----------+------+-------------------------------------------+
| host      | user | password                                  |
+-----------+------+-------------------------------------------+
| localhost | root | *XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX |
| 127.0.0.1 | root | *XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX |
| ::1       | root | *XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX |
| localhost |      |                                           |
+-----------+------+-------------------------------------------+
   
-- logout and terminate the client program
mysql> quit
Bye
Explanation
  • SELECT host, user, password FROM mysql.user;
    This command lists all the existing users, kept in the system database "mysql" table "user". You can refer to a table by databasename.tablename, i.e., mysql.user. Observe that four user accounts are installed by default: 'root'@'localhost', 'root'@'127.0.0.1', 'root'@'::1' and ''@'localhost' (this is an anonymous user with empty string as the username), all WITHOUT passwords (or empty string as password). Take note that a MySQL user is identified by three attributes: username, password, and the IP address (or hostname) of the client's machine. For example, the user root can only login from the localhost, or IPv4 127.0.0.1, or IPv6 ::1; but NOT from other IP addresses (or hostnames).
  • A command can span more than one line. You have to terminate each command with a semicolon (;). Otherwise, a "->" prompt will appear to prompt for the rest of the command. Enter a ';' to complete the command; or '\c' to cancel the command. For example,
    mysql> select host, user, password from mysql.user;     
    ......
     
    mysql> select host, user, password from mysql.user
        -> ;
    ......
     
    mysql> select 
        -> host, user, password
        -> from mysql.user;
    ...... 
       
    mysql> select host, u \c
     
        '> ' \c
        "> " \c
    Semicolon terminates the command,
      and sends the command to the server for processing.
     
    This command is not complete, to be continued in the next line.
    The semicolon terminates the command, and sends it to the server.
       
      
    A command can span several lines, terminated by a semicolon.
      
       
       
      
    "\c" cancels the command, and does not send it to the server.
     
    If the prompt changes to '>, type ' \c to cancel the command.
    If the prompt changes to ">, type " \c to cancel the command. 
  • SET PASSWORD FOR 'root'@'localhost'=password('xxxx');
    You can set the password for 'root'@'localhost', 'root'@'127.0.0.1' and 'root'@'::1' using the "set password" command, where 'xxxx' denotes your chosen password.
  • "localhost" is a special hostname, meant for local loop-back (i.e., the server is running in the same machine as the client). It has the IPv4 address of 127.0.0.1, and IPv6 address of ::1.
  • Issue "quit", "exit", or press control-c to terminate the client.
  • During a client session, you can issue "help" or "\h" for help.
Start a Client with Password

We have just set a password for root user and exited the client. Start a client and login as root again. Enter the password when prompted.

For Windows

-- Change the current working directory to <MYSQL_HOME>\bin
D:\myProject\mysql\bin> mysql -u root -p
Enter password:    // Type your password and enter. NOTHING will be shown for security.
Welcome to the MySQL monitor.
......  
-- client started, ready to issue SQL command
mysql>

For Mac OS X

-- Change the current working directory to /usr/local/mysql/bin
$ cd /usr/local/mysql/bin
$ ./mysql -u root -p
Enter password:    // Type your password and enter. NOTHING will be shown for security.
Welcome to the MySQL monitor.
......  
-- client started, ready to issue SQL command
mysql>
Remove the Anonymous User

For security reason, remove the anonymous user (identified by an empty-string username) as follows:

mysql> drop user ''@'localhost';
   
mysql> select host, user, password from mysql.user;
+-----------+------+-------------------------------------------+
| host      | user | password                                  |
+-----------+------+-------------------------------------------+
| localhost | root | *XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX |
| 127.0.0.1 | root | *XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX |
| ::1       | root | *XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX |
+-----------+------+-------------------------------------------+
3 rows in set (0.00 sec)
   
mysql> quit

Step 6: Create a New User

The superuser "root" is privileged, which is meant for database administration and is not meant for day-to-day usage. We shall create a new user - let's call it "myuser" - with a lesser privilege. To create a new user, start a client with superuser "root":

-- Start a client, if it is not started
> mysql -u root -p     // Windows
$ ./mysql -u root -p   // Mac OS X
   
-- Create a new user called "myuser", which can login from localhost, with password "xxxx"
mysql> create user 'myuser'@'localhost' identified by 'xxxx';
Query OK (0.01 sec)
   
-- Grant permission to myuser
mysql> grant all on *.* to 'myuser'@'localhost';
Query OK (0.01 sec)
   
-- Query all users and passwords
mysql> select host, user, password from mysql.user;
+-----------+--------+-------------------------------------------+
| host      | user   | password                                  |
+-----------+--------+-------------------------------------------+
| localhost | root   | *XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX |
| 127.0.0.1 | root   | *XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX |
| ::1       | root   | *XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX |
| localhost | myuser | *XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX |
+-----------+--------+-------------------------------------------+
4 rows in set (0.00 sec)
   
mysql> quit
Explanation
  • CREATE USER 'myuser'@'localhost' IDENTIFIED BY 'xxxx'
    We use the command "create user" to create a new user called 'myuser'@'localhost', who can login to the server locally from the same machine (but not remotely from another machine), with password "xxxx".
  • GRANT ALL ON *.* TO 'myuser'@'localhost'
    The newly created user has NO privilege to perform any database operation including select. We use the "grant" command to grant "all" the privileges (including select, insert, delete, and so on) to this new user on ALL the databases and ALL the tables ("on *.*"). This new user, in practice, has the same privilege as root, except that it cannot issue grant command. For production, you should grant only the necessary privileges on selected databases and selected tables, e.g., "grant select, insert, update on studentdb.*" - it can issue select, insert and update (but no delete, create/drop table) on ALL the tables of the database studentdb only.

Step 7: Create a new Database, a new Table in the Database, Insert Records, Query and Update

A MySQL server contains many databases (aka schema). A database consists of many tables. A table contains rows (records) and columns (fields).

Let's create a database called "studentdb", and a table called "class101" in the database. The table shall have three columns: id (of the type INT - integer), name (of the type VARCHAR(50) - variable-length string of up to 50 characters), gpa (of the type FLOAT - floating-point number).

CAUTION: Programmers don't use blank and special characters in names (database names, table names, column names). It is either not supported, or will pose you many more challenges.

TIPS: Before we proceed, here are some tips on using the client:

  • You need to terminate your command with a semicolon (;), which sends the command to the server for processing.
  • A command can span several lines, and terminated by a semicolon (;).
  • You can use \c to cancel (abort) the current command (or '\c if the prompt changes to '>; or "\c if the prompt changes to ">).
  • You can use up/down arrow keys to retrieve the previous/next commands (from the history commands).
  • (For Windows) You should enable copy/paste functions of CMD shell. To enable copy/paste, click the CMD's icon ⇒ Properties ⇒ Options ⇒ Edit Options ⇒ Check "QuickEdit Mode". You can then select the desired texts and use a "right-click" to copy the selected text; another "right-click" to paste.

Let's start a client with our newly-created user "myuser".

-- Start a client, if it is not started
-- cd to the MySQL's bin directory
> mysql -u myuser -p     // Windows
$ ./mysql -u myuser -p   // Mac OS X
   
-- Create a new database called "studentdb"
mysql> create database if not exists studentdb;
Query OK, 1 row affected (0.08 sec)
   
-- list all the databases in this server
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| studentdb          |
| test               |
+--------------------+
5 rows in set (0.07 sec)
   
-- Use "studentdb" database as the default database
-- You can refer to tables in the default database by tablename alone, instead of databasename.tablename
mysql> use studentdb;
Database changed
   
-- Remove the table "class101" in the default database if it exists
mysql> drop table if exists class101;
Query OK, 0 rows affected (0.15 sec)
   
-- Create a new table called "class101" in the default database 
--  with 3 columns of the specified types
mysql> create table class101 (id int, name varchar(50), gpa float);
Query OK, 0 rows affected (0.15 sec)
   
-- List all the tables in the default database "studentdb"
mysql> show tables;
+---------------------+
| Tables_in_studentdb |
+---------------------+
| class101            |
+---------------------+
1 row in set (0.00 sec)
   
-- Describe the "class101" table (list its columns' definitions)
mysql> describe class101;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| id    | int(11)     | YES  |     | NULL    |       |
| name  | varchar(50) | YES  |     | NULL    |       |
| gpa   | float       | YES  |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
3 rows in set (0.04 sec)
   
-- Insert a row into "class101" table.
-- Strings are to be single-quoted. No quotes for INT and FLOAT.
mysql> insert into class101 values (11, 'Tan Ah Teck', 4.8);
Query OK, 1 row affected (0.03 sec)
   
-- Insert another row
mysql> insert into class101 values (22, 'Mohamed Ali', 4.9);
Query OK, 1 row affected (0.03 sec)
   
-- Select all columns (*) from table "class101"
mysql> select * from class101;
+----+-------------+------+
| id | name        | gpa  |
+----+-------------+------+
| 11 | Tan Ah Teck |  4.8 |
| 22 | Mohamed Ali |  4.9 |
+----+-------------+------+
2 rows in set (0.00 sec)
  
-- Select columns from table "class101" with criteria
mysql> select name, gpa from class101 where gpa > 4.85;
+-------------+------+
| name        | gpa  |
+-------------+------+
| Mohamed Ali |  4.9 |
+-------------+------+
1 rows in set (0.00 sec)
  
-- Update selected records
mysql> update class101 set gpa = 4.4 where name = 'Tan Ah Teck';
Query OK, 1 row affected (0.03 sec)
   
mysql> select * from class101;
+----+-------------+------+
| id | name        | gpa  |
+----+-------------+------+
| 11 | Tan Ah Teck |  4.4 |
| 22 | Mohamed Ali |  4.9 |
+----+-------------+------+
2 rows in set (0.00 sec)
 
-- delete selected records
mysql> delete from class101 where id = 22;
Query OK, 1 row affected (0.03 sec)
   
mysql> select * from class101;
+----+-------------+------+
| id | name        | gpa  |
+----+-------------+------+
| 11 | Tan Ah Teck |  4.4 |
+----+-------------+------+
1 rows in set (0.00 sec)
 
-- You can store SQL commands in a file (called SQL script) and run the script.
-- Use a text editor to CREATE a NEW FILE called "mycommands.sql" 
--   containing the following three SQL statements.
-- (For Windows) Save the file under "d:\myProject".
-- (For Mac OS X) Save the file under "Documents".
insert into class101 values (33, 'Kumar', 4.8);
insert into class101 values (44, 'Kevin', 4.6);
Select * from class101;

-- Once you have created the file, you can use the following "source" command 
--   to run the SQL script.
-- You need to provide the full path to the script.
-- (For Windows) The filename is d:\myProject\mycommands.sql.
-- (For Mac OS X) The filename is ~/Documents/mycommands.sql
mysql> source d:\myProject\mycommands.sql   // For Windows
mysql> source ~/Documents/mycommands.sql    // For Mac OS X
Query OK, 1 row affected (0.00 sec)   -- INSERT command output
Query OK, 1 row affected (0.00 sec)   -- INSERT command output
+------+-------------+------+         -- SELECT command output
| id   | name        | gpa  |
+------+-------------+------+
|   11 | Tan Ah Teck |  4.4 |
|   33 | Kumar       |  4.8 |
|   44 | Kevin       |  4.6 |
+------+-------------+------+
3 rows in set (0.00 sec)
Exercises:
  1. Select records with names starting with letter 'K'. (Hints: name like 'K%')
  2. Select records with names NOT starting with letter 'K'. (Hints: name NOT like ...)
  3. Select records with gpa between 4.35 and 4.65. (Hints: gpa >= 4.3 AND ...)
  4. Select records with names having a letter 'e'. (Hints: name like '%e%')
  5. Select records with names having a letter 'e' or 'a'. (Hints: ... OR ...)
  6. Select records with names NOT having a letter 'e' or 'a'. (Hints: NOT (... OR ...))
  7. Select records with names having a letter 'e' and gpa ≥ 4.5.

(Skip Unless... ) Read "Common Problems in Using the mysql Client".

More Exercises

  1. Show all the databases.
  2. Create a new database called "ABCTrading".
  3. Set the "ABCTrading" database as the default database.
  4. Show all the tables in the default database.
  5. Create a new table called "products" with the columns and type indicated below.
    +-------+----------+-------------+----------+---------+
    | id    | category | name        | quantity | price   |
    | (INT) | CHAR(3)  | VARCHAR(20) | (INT)    | (FLOAT) |
    +-------+----------+-------------+----------+---------+
    | 1001  | PEN      | Pen Red     |     5000 |  1.23   |
    | 1002  | PEN      | Pen Blue    |     8000 |  1.25   |
    | 1003  | PEN      | Pen Black   |     2000 |  1.25   |
    | 1004  | PCL      | Pencil 2B   |    10000 |  0.49   |
    | 1005  | PCL      | Pencil 2H   |     9000 |  0.48   |
    +-------+----------+-------------+----------+---------+
  6. Show the table description.
  7. Insert the above records and list all the records.
  8. List records with name containing "Pencil".
  9. List records with price ≥ 1.0.
  10. Increase the price of all items by 10%, and list all the records.
  11. Remove "Pen Red" from the table, and list all the records.

Many-to-many Relationship

In a bookstore, a book is written by one or more authors; an author may write zero or more books. This is known as a many-to-many relationship. It is IMPOSSIBLE to capture many-to-many relationship in a SINGLE table with a fixed number of columns, without duplicating any piece of information! For example, if we organize the data in the table below, we will not know how many author columns to be used; and we need to repeat all the data for repeating authors.

many-to-many

The many-to-many relationship between books and authors can be modeled with 3 tables, as shown below. A books table contains data about books (such as title and price); an authors table contains data about the authors (such as name and email). A table called books_authors joins the books and authors tables and captures the many-to-many relationship between books and authors.

image
Exercises
  1. Create a database called "mybookstore".
  2. Use "mybookstore" as the default database.
  3. Create 3 tables "books", "authors", and "books_authors" in the database "mybookstore", with column names and types as shown.
  4. Insert the respective records into the tables. List the contents of each of the tables (via SELECT * from tableName command).
  5. Try this query and explain the output:
    SELECT books.title, books.price, authors.name
       FROM books, books_authors, authors
       WHERE books.isbn = books_authors.isbn
          AND authors.authorID = books_authors.authorID
          AND authors.name = 'Tan Ah Teck';
    NOTES: When you SELECT from more than one tables, all combinations of rows would be available. In other words, if table1 has n1 rows, table2 has n2 rows, there will be n1×n2 rows available. The WHERE clause is used to filter the n1×n2 rows.
  6. List all the books (title, price, qty) by "Tan Ah Teck" with price less than 20.
  7. List all the authors (name and email) for the book title "Java for Dummies".
  8. List all the books (title, price, qty) and all the authors (name and email) for books with title beginning with "Java" (Hints: title LIKE 'Java%').

Backup and Restore Databases

Backup via "mysqldump" Utility Program

You can use the "mysqldump" utility program to back up the entire server (all databases), selected databases, or selected tables of a database. The "mysqldump" program generates a SQL script that can later be executed to re-create the databases, tables and their rows.

For example, the following command backups the entire "studentdb" database to a SQL script called "backup_studentdb.sql".

For Windows

-- Start a NEW "cmd"
> cd path-to-mysql-bin
> mysqldump -u myuser -p --databases studentdb > "d:\myProject\backup_studentdb.sql"

For Mac OS X

-- Start a NEW "terminal"
$ cd /usr/local/mysql/bin
$ ./mysqldump -u myuser -p --databases studentdb > ~/Documents/backup_studentdb.sql
     // ~ denotes the home directory of the current login user

Study the output file, which contains CREATE DATABASE, CREATE TABLE and INSERT statements to re-create the database and tables dumped.

Restore via "source" command in a mysql client

You can restore from the backup by running the "source" command in a MySQL client. For example, to restore the studentdb backup earlier:

For Windows

-- Start a MySQL client
> cd path-to-mysql-bin
> mysql -u myuser -p
-- Run the backup script to recreate the database
mysql> drop database if exists studentdb;
mysql> source d:\myProject\backup_studentdb.sql

For Mac OS X

-- Start a MySQL client
$ cd /usr/local/mysql/bin
$ ./mysql -u myuser -p
-- Run the backup script to recreate the database
mysql> drop database if exists studentdb;
mysql> source ~/Documents/backup_studentdb.sql

Summary of Frequently-Used Commands

(For Windows) Starting MySQL Server and Client
-- Start the Server
> cd path-to-mysql-bin
> mysqld --console
 
-- Shutdown the Server
Ctrl-c
 
-- Start a Client
> cd path-to-mysql-bin
> mysql -u username -p
(For Mac OS X) Starting MySQL Server and Client
-- Start the Server
$ cd /usr/local/mysql/bin
$ sudo ./mysqld_safe --console
 
-- Shutdown the Server
-- Start another terminal
$ cd /usr/local/mysql/bin
$ sudo ./mysqladmin -u root -p shutdown
 
-- Start a Client
$ cd /usr/local/mysql/bin
$ ./mysql -u username -p
Frequently-used MySQL Commands

MySQL commands are NOT case sensitive.

-- General
STATUS      -- Displays status such as port number
;           -- Sends command to server for processing (or \g)
\c          -- Cancels (aborts) the current command
\G          -- Displays the row vertically
 
-- Database-level
DROP DATABASE databaseName                 -- Deletes the database
DROP DATABASE IF EXISTS databaseName       -- Deletes only if it exists
CREATE DATABASE databaseName               -- Creates a new database
CREATE DATABASE IF NOT EXISTS databaseName -- Creates only if it does not exists
SHOW DATABASES                             -- Shows all databases in this server
   
-- Set default database.
-- Otherwise you need to use the fully-qualified name, in the form 
--   of "databaseName.tableName", to refer to a table.
USE databaseName
SELECT DATABASE();       -- show the default database
   
-- Table-level
DROP TABLE tableName
DROP TABLE IF EXISTS tableName
CREATE TABLE tableName (column1Definition, column2Definition, ...)
CREATE TABLE IF NOT EXISTS tableName (column1Definition, column2Definition, ...)
SHOW TABLES              -- Shows all the tables in the default database
DESCRIBE tableName       -- Describes the columns for the table
DESC tableName           -- Same as above
   
-- Record-level (CURD - create, update, read, delete)
INSERT INTO tableName VALUES (column1Value, column2Value,...)
INSERT INTO tableName (column1Name, ..., columnNName) 
   VALUES (column1Value, ..., columnNValue)
DELETE FROM tableName WHERE criteria
UPDATE tableName SET columnName = expression WHERE criteria
SELECT column1Name, column2Name, ... FROM tableName 
   WHERE criteria
   ORDER BY columnAName ASC|DESC, columnBName ASC|DESC, ...
  
-- Running a script of MySQL statements
SOURCE full-Path-Filename
Link to MySQL References & Resources