MySQL storage types and their limits

Below are some of the most used data types and its storage requirements:

Data type Storage required
TINYINT 1 byte
SMALLINT 2 bytes
MEDIUMINT 3 bytes
INT 4 bytes
 BIGINT 8 bytes
FLOAT 4 bytes
DOUBLE, REAL 8 bytes
VARCHAR(x) x+1 byte if value is less than 255 bytes and x+2 bytes if over 255 bytes.
TINYTEXT 255 bytes
TEXT 65 535 bytes
MEDIUMTEXT 16 777 215 bytes
LONGTEXT 4 294 967 295 bytes

Notes:

  • Characters can take up different amount of space depending on character encoding. Regular English ASCII characters only take 1 byte per character, meaning that a TEXT column can fit 65 535 characters (a-Z, 0-9 and some special signs)
  • VARCHAR(180) will require 181 bytes of space, regardless if it’s empty or not.

Date formats:

Data type < MySQL 5.6.4 > MySQL 5.6.4
YEAR 1 byte 1 byte
DATE 3 bytes 3 bytes
TIME 3 bytes 3 bytes + fractional seconds storage
DATETIME 8 bytes 5 bytes + fractional seconds storage
TIMESTAMP 4 bytes 4 bytes + fractional seconds storage

Sources:

Add remote access to MySQL server

Follow the commands below to setup a new user and open up for remote access to a specific database on your MySQL server.

$ mysql -u root -p
    Enter your MySQL root password.
mysql> CREATE USER 'itdb_admin';
mysql> CREATE DATABASE itdb_db;
mysql> GRANT ALL PRIVILEGES ON itdb_db.* to 'itdb_admin'@'%' IDENTIFIED BY 'my-password' WITH GRANT OPTION;
mysql> FLUSH PRIVILEGES;
mysql> EXIT;
$ sudo nano /etc/mysql/my.cnf
    Comment the following line (to disable it):
    bind-address        = 127.0.0.1
$ sudo service mysql restart

Quick summary:

1) Open the MySQL CLI
2) Create a new database
3) Create a new user
4) Give the user full access to the database. Notice the '%' which means we’re talking about remote access. The same user can have different access levels based on the connection (whether it’s remote or local)
5) Flush/refresh the privileges so they become active
6) Disable bind-address so the MySQL server will listen on any source address
7) Restart the MySQL service to reload the config file

Backup MySQL data using mysqldump

Backup complete database:

mysqldump -u <username> -p<password> <dbname> > dbname.sql

Backup only specific tables:

mysqldump -u <username> -p<password> <dbname> <tablename> \ > tablename.sql

Restore a .sql file:

mysql -u <username> -p<password> <dbname> < file.sql

Note: There can’t be any empty spaces between -p and the password parameter.

Examples:

mysqldump -u root -p123456 itdb > itdb_280912.sql
mysqldump -u root -p123456 itdb itdb_posts \ > itdb_posts_280912.sql
mysql -u root -p123456 itdb < itdb_backup.sql

Setup automated database backup with mysqldump and cron jobs for Linux

Start cron manager by running command $ crontab -e and type the following line at the bottom:

0 4 * * * sudo mysqldump -u root -p<password> <dbname> | gzip > /mnt/nas/<dbname>_bak_`data ' %Y-%m-%d'`.sql.gz

This will create a job entry in cron which starts every night at 0400 AM. What it does is running mysqldump to backup the specified <dbname> and also compresses it to a gzip file and saves it to /mnt/nas/ (replace with wherever you want to store the file).