Difference between revisions of "MySQL"

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m (Added example of deleting a row)
m (Added comment examples)
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* ? characters for password length
 
* ? characters for password length
 
** Seems to be dependent on the version
 
** Seems to be dependent on the version
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== Using comments ==
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<ref name="mysql-valid-comment-styles" />
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These are all valid comment styles.
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<syntaxhighlight lang="mysql" enclose="div">
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# Comment 1
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-- Comment 2
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/*
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    Comment 3
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*/
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</syntaxhighlight>
  
  
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<ref name="mysql-wikibooks-cheatsheet">[http://en.wikibooks.org/wiki/MySQL/CheatSheet WikiBooks - MySQL CheatSheet]</ref>
 
<ref name="mysql-wikibooks-cheatsheet">[http://en.wikibooks.org/wiki/MySQL/CheatSheet WikiBooks - MySQL CheatSheet]</ref>
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<ref name="mysql-valid-comment-styles">[http://stackoverflow.com/questions/728172/are-there-multiline-comment-delimiters-in-sql-that-are-vendor-agnostic Are there multiline comment delimiters in SQL that are vendor agnostic?]</ref>
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</references>
 
</references>

Revision as of 15:51, 16 March 2014


Character length restrictions

[1] [2]

  • 64 characters for database name
  • 16 characters for user name
  •  ? characters for password length
    • Seems to be dependent on the version


Using comments

[3]

These are all valid comment styles.

# Comment 1
-- Comment 2
/*
 
    Comment 3

*/


Create a database

CREATE DATABASE my_test_db CHARACTER SET utf8;


Create a user for that database with full privileges to it

CREATE USER 'my_test_db_usr'@'localhost' IDENTIFIED BY 'INITIAL_PASSWORD';
GRANT ALL PRIVILEGES ON my_test_db.* TO 'my_test_db_usr'@'localhost';


Reset password for user account

SET PASSWORD for 'my_test_db_usr'@'localhost' = PASSWORD('REAL_PASSWORD_HERE');


Import or run SQL statements from file

source my-sql-file.sql;


Insert a new row

[4]

  INSERT INTO table_name (
      `field_name1`, 
      `field_name2`, 
      `field_name3`
  )
  VALUES (
      'Value1', 
      'Value2', 
      'Value3'
  );


Update field

[4]

UPDATE table_name SET table_field = 'Value' WHERE id = '1';


Delete row

DELETE FROM virtual_domains WHERE id = '1' OR id = '7';


Delete user account

DROP USER 'my_test_db_usr'@'localhost';


Delete database

DROP DATABASE 'my_test_db';


Resetting the root user account

[5] [6]

More Secure

1 nano /home/me/FILE
2 # Add SQL statement from section below
3 # Save & quit nano
4 sudo /etc/init.d/mysql stop
5 mysqld_safe --init-file=/home/me/FILE &
6 rm /home/me/FILE
7 sudo /etc/init.d/mysql restart

Less secure

1 sudo /etc/init.d/mysql stop
2 sudo mysqld --skip-grant-tables &
3 mysql -u root mysql
4 UPDATE user SET Password=PASSWORD('YOURNEWPASSWORD') WHERE User='root'; FLUSH PRIVILEGES; exit;


Viewing privileges granted to a user

[7] [8]

  • select * from mysql.user;
    
    • Parse results by eye (not pretty)
  • SHOW GRANTS FOR username@ipaddress;
    
  • SHOW GRANTS;
    
    • For current user


Show the character set for a database

[9]

SHOW CREATE DATABASE database_name;


Show the database engine type

[10]

USE DATABASE database_name;
SHOW CREATE TABLE table_name;


References

  1. 6.3.1 User Names and Passwords
  2. 9.2 Schema Object Names
  3. Are there multiline comment delimiters in SQL that are vendor agnostic?
  4. 4.0 4.1 WikiBooks - MySQL CheatSheet
  5. Set / Change / Reset the MySQL root password on Ubuntu Linux
  6. MySQL :: MySQL 5.0 Reference Manual :: C.5.4.1 How to Reset the Root Password
  7. How can I show user's privileges in MySQL?
  8. How to show user privileges on mysql
  9. How do I see what character set a database / table / column is in MySQL?
  10. How can I check MySQL engine type for a specific table?