This is to allow users to practice MySQL commands or execute complex queries on the database.

“test” database is accessible to everyone who has access to MySQL in your localhost and hence is not advisable if you were to use it for your development.

Instead, create a database with specific user privileges if you have user rights or request your administrator to create one for you.

A simple MySQL statement to create a user with all privileges to the database.

$ grant all on newdb.* to ‘newdbuser’@localhost identified by ‘newdbuser_password’;

c:\mysql\bin> net start mysql

To stop MySQL service from Windows command prompt

c:\mysql\bin> net stop mysql

The list will continue to grow …

Choosing the right data type can create significant improvement in application performance.

Many programmers/developers who opt to choose MySQL as the backend for their operations often fail miserably in choosing the most efficient data types.

MySQL Numeric Data type:

To explain the above table a bit more, let us take the first row where it gives the values for “Tinyint” data type. It states “Bytes” = 1 which means TINYINT data type has 1 Byte which is equal to 8 bits (n = 8). Maximum signed value for TINYINT is given to be 127 and the calculation for it is [2^(n-1) - 1] = [2^(8-1) - 1]

To test the maximum value for TINYINT data type in MySQL try creating a table with a column whose data type is TINYINT. Then try inserting into TINYINT field the following values 126, 127 and 128 to know the difference.

On inserting the value 128 into TINYINT field you will get the following warning message and the value resets to 127
Warning: #1264 Out of range value adjusted for column ‘mytinyintcolumn’ at row 1

When declaring the table, we assign the value TINYINT(2). Some may not understand what that “2″ is for. This is the value for padding to the left during display. Set the attribute to ZEROFILL and then try testing with different combinatios for “value” field and you will be able to notice the way the display is affected with different left-padding settings.

Step 1: First we need to check MySQL is installed by issuing the following command
[root@user Desktop]# which mysql

If you get …
/usr/bin/mysql
then, it is an indication that MySQL is installed in your machine.

If you get …
which: no mysql in (/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin)

This will give an indication if MySQL is installed or not. If it is not installed then issue
[root@user Desktop]# yum install mysql

Step 2: Then check if PHP installed by issuing the command
[root@user Desktop]# which php

If you get …
/usr/bin/php
then, it is an indication that PHP is installed in your machine.

To get the version of PHP installed in your machine, type
[root@user Desktop]# php –version

If php is not installed then type
[root@user Desktop]# yum install php

Step 3: phpMyAdmin pre-configuration steps
[root@user Desktop]# yum install php-gd php-mcrypt php-mbstring
We first install a set of Apache HTTP Server modules required for phpMyAdmin

Download location for phpMyAdmin

http://www.phpmyadmin.net/home_page/downloads.php

Step 4: phpMyAdmin configuration on CentOS/RedHat
Create the configuration file by typing the following command
[root@user Desktop]# cp /var/www/html/phpMyAdmin/config.sample.inc.php /var/www/html/phpMyAdmin/config.inc.php

Edit the configuration settings of phpMyAdmin
[root@user Desktop]# vi /var/www/html/phpMyAdmin/config.inc.php

The following is a basic setting for phpMyAdmin configuration. You can play with the below setting
by assigning user name, password or setting the authentication type to ‘cookie’ instead of ‘http’ or
having a different folder setting for saving/loading files.

/* Authentication type */
$cfg['Servers'][$i]['auth_type'] = ‘http’;
/* Server parameters */
$cfg['Servers'][$i]['host'] = ‘localhost’;
$cfg['Servers'][$i]['connect_type'] = ‘tcp’;
$cfg['Servers'][$i]['compress'] = true;
/* Select mysqli if your server has it */
$cfg['Servers'][$i]['extension'] = ‘mysql’;
/* User for advanced features */
$cfg['Servers'][$i]['controluser'] = ”;
$cfg['Servers'][$i]['controlpass'] = ”;
.
.
.
.
/*
* Directories for saving/loading files from server
*/
$cfg['UploadDir'] = ‘tmp’;
$cfg['SaveDir'] = ‘tmp’;

Step 5: Permission settings for the configuration file – phpMyAdmin
After making the necessary changes, type the following command change the permission of the
configuration file to not allow world to read or write.
[root@user Desktop]# chmod -R 0750 /var/www/html/phpMyAdmin/config.inc.php

ERROR 1:
If you had moved phpMyAdmin extracted folder into /var/www/html/phpMyAdmin you might get a message (SELinux: AVC denial error),

SELinux is preventing the httpd from using potentially mislabeled files (/var/www/html/phpMyAdmin).

In the above case, type
[root@user Desktop]# restorecon -R -v ‘/var/www/html/phpMyAdmin’

Now browse to the folder, http://localhost/phpMyAdmin and the you should be able to see phpMyAdmin
interface.

If there are any version conflicts related to PHP, those get shown for you now. Depending on the
PHP version, that is intalled in your machine, you can download the related phpMyAdmin

ERROR 2:
If you have not set a password for the default ‘root’ account when you installed MySQL, you will
get the error “Your configuration file contains settings (root with no password) that corresponds to
the default MySQL privileged account. Your MySQL server is running with this default, is open to
intrusion, and you really should fix this security hole.”

If this is the case then follow the below set of instructions
[root@user Desktop]# mysql -uroot
mysql> set password for ‘root’@'localhost’ password = PASSWORD(‘your_password’);
mysql> quit;

This will remove the error message that will see in the phpMyAdmin interface when default password
for the ‘root’ user is not set.