MySQL Database Points
This tutorial explain about MySQL database running on a Linux server. This tutorial will make you understand how to install and setup MySQL database server and how to use basic MySQL queries/command, which initially we use in MySQL database.
- Introduction and use of Database
- Installation and Configuration
- To Login and exit from Database
- Data types explain
- Database Storage engines
A brief Introduction about MySQL database
What is Database?
A database is a collection of information so that it can easily be accessed, managed, and updated.
What is MySQL Database?
MySQL is an open source database management software that helps user to store, organize, and retrieve data. MySQL offers great reliability and easy to use and maintain the record in DB. Purpose of using database is to get rid the manual task into diary or other documentary. MySQL, pronounced either “My S-Q-L” or “My Sequel,” It is based on the structure query language (SQL). Standard MySQL commands, such as ADD, DROP, INSERT, and UPDATE can be used.
Install and Configure MySQL Database Server in CentOS/RHEL
Install MySQL package in Centos/RHEL/5 & 6 distribution
Install the MySQL server package through the CentOS/RHEL repository.
[root@master ~]#yum install mysql mysql-server
Start Mysql Service.
[root@master ~]# service mysqld restart
Check MySQL service status
[root@master ~]# service mysqld status
Permanently on MySQL service on startup
[root@master ~]# chkconfig mysqld on
Identify on which ports MySQL work
[root@master ~]# netstat -tunlp | grep mysqldtcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 1657/mysqld
Setup MySQL root user password
To create root password for first time, use mysqladmin command at shell prompt as follows:
[root@master ~]# mysqladmin -u root password [newpasswordhere]
Example;
[root@master ~]# mysqladmin -u root password kvit@123
Change/reset MySQL root password
[root@master ~]#mysqladmin -u root -p[oldpassword] password [newpass]
Example;
[root@master ~]#mysqladmin -u root -pkvit@123 password kvit@321
Setup MySQL database using mysql_secure_installation command
Alternatively, you can run the below command mysql_secure_installation from the Linux root user, to complete the fields that make sense for your MySQL configuration.
We recommend that you configure the following secure settings:
- Set a password for the MySQL root user.
- Remove MySQL anonymous users.
- Disallow remote login for the MySQL root user.
- The MySQL root user is allowed to connect to the database, but only from the local host.
- Remove the test database.
- Reload the Privileges table.
[root@master1 ~]# /usr/bin/mysql_secure_installation
output;
NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MySQL
SERVERS IN PRODUCTION USE! PLEASE READ EACH STEP CAREFULLY!
In order to log into MySQL to secure it, we’ll need the current
password for the root user. If you’ve just installed MySQL, and
you haven’t set the root password yet, the password will be blank,
so you should just press enter here.
Enter current password for root (enter for none): (type password here if you already generate root password or hit enter if not )
OK, successfully used password, moving on…
Setting the root password ensures that nobody can log into the MySQL
root user without the proper authorisation.
You already have a root password set, so you can safely answer ‘n’.
Change the root password? [Y/n] y
New password:
Re-enter new password:
Password updated successfully!
Reloading privilege tables..
… Success!
By default, a MySQL installation has an anonymous user, allowing anyone
to log into MySQL without having to have a user account created for
them. This is intended only for testing, and to make the installation
go a bit smoother. You should remove them before moving into a
production environment.
Remove anonymous users? [Y/n] y
… Success!
Normally, root should only be allowed to connect from ‘localhost’. This
ensures that someone cannot guess at the root password from the network.
Disallow root login remotely? [Y/n] y
… Success!
By default, MySQL comes with a database named ‘test’ that anyone can
access. This is also intended only for testing, and should be removed
before moving into a production environment.
Remove test database and access to it? [Y/n] y
– Dropping test database…
… Success!
– Removing privileges on test database…
… Success!
Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.
Reload privilege tables now? [Y/n] y
… Success!
Cleaning up..
All done! If you’ve completed all of the above steps, your MySQL
installation should now be secure.
Thanks for using MySQL!
Login into MySQL Database
Login in to MySQL database as root user
[root@master ~]# mysql -u root –p
Password: *******
output;
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 17
Server version: 5.1.73 Source distribution
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respectiveowners.
Type ‘help;’ or ‘\h’ for help. Type ‘\c’ to clear the current input statement.
mysql>
Exit from MySQL database
mysql> exit;
Bye
[root@master ~]#
Note: After settings the mysql root password from bash sehll, clear the password history from .bash_historyfile
Shell/bash command history saved in
[root@master ~]# vim .bash_history
MySQL database queryhistory saved in
[root@master ~]# vim .mysql_history
MySQL Data type reference
Numeric Data Types
TinyInt – A very small integer with a signed range of -128 to 127 and an unsigned range of 0 to 255 .
SmallInt – A small integer with a signed range of -32768 to 32767 and an unsigned range of 0 to 65535 .
MediumInt– A medium sized integer with a signed range of -8388608 to 8388607 and an unsigned range of 0 to 16777215 .
Int (Integer) – It can store 0 to 255 characters. holds a fixed length string (can contain letters, numbers, and special characters). The fixed size is specified in parenthesis.
Bigint– A large integer with a signed range of -9223372036854775808 to 9223372036854775807 and an unsigned range of 0 to 18446744073709551615.
String/text Datatype
VARCHAR(size) –It Holds a variable length string (letters, numbers, and special characters). The maximum size is specified in parenthesis. Can store up to 255 characters.
CHAR(size) – Holds a fixed length string (can contain letters, numbers, and special characters). The fixed size is specified in parenthesis. Can store up to 255 characters
Date and Time data type
DATE YYYY-MM-DD
DATETIME YYYY-MM-DD HH:MM:SS
TIMESTAMP YYYYMMDDHHMMSS
TIME HH:MM:SS
Database Storage engines
MySQL provides support for different storage engines which act as varying table type handlers. Two most common storage engines are MyISAM and InnoDB. Most of the time, the default storage engine as defined by the store_engine option in the MySQL config file is typically MyISAM.
- MyISAM
- InnoDB
- MERGE
- MEMORY (HEAP)
- ARCHIVE
- CSV
Differents between MyISAM and InnoDB.
MyISAM – This manages non transactional tables, provides high-speed storage and retrieval, supports full text searching.
InnoDB –It provides transaction-safe (ACID compliant) tables, supports FOREIGN KEY referential-integrity constraints. It supports commit, rollback, and crash-recovery capabilities to protect data.
—
This is all about basic concept of MySQL database server to perform some administration task, later we will post some useful MySQL command in our next tutorial.
Post a Comment