MySQL in a Nutshell [49]
UPDATE teachers
SET pwd = ENCRYPT('test', 'JT')
WHERE teacher_id = '730522';
Name
MD5( )
Synopsis
MD5(string)
This function uses a Message-Digest algorithm 5 (MD5) 128-bit checksum to return a 32-character hash value of string from the Request for Comments (RFC) 1321 standard. Here is an example:
SELECT MD5('Test') AS 'MD5( ) Test';
+----------------------------------+
| MD5( ) Test |
+----------------------------------+
| 0cbc6611f5540bd0809a388dc95a615b |
+----------------------------------+
Name
OLD_PASSWORD( )
Synopsis
OLD_PASSWORD(string)
This function encrypts a given string based on the password encryption method used prior to version 4.1 of MySQL. The result cannot be decrypted. Here is an example:
UPDATE teachers
SET pwd = OLD_PASSWORD('test')
WHERE teacher_id = '730522';
Name
PASSWORD( )
Synopsis
PASSWORD(string)
This function encrypts a password given as an argument. The result cannot be decrypted. This function is used for encrypting data in the password column of the user table in the mysql database. Here is an example:
UPDATE teachers
SET pwd = PASSWORD('test')
WHERE teacher_id = '730522';
Name
SESSION_USER( )
Synopsis
SESSION_USER( )
This function returns the username and the hostname for the current MySQL connection. The function takes no arguments. It’s synonymous with SYSTEM_USER( ) and USER( ).
Name
SHA( )
Synopsis
SHA(string)
This function returns the Secure Hash Algorithm (SHA) 160-bit checksum for the given string. The result is a string composed of 40 hexadecimal digits. NULL is returned if the given string is NULL. This function is synonymous with SHA1( ). Here is an example:
SELECT SHA('test');
+------------------------------------------+
| SHA('test') |
+------------------------------------------+
| a94a8fe5ccb19ba61c4c0873d391e987982fbbd3 |
+------------------------------------------+
Name
SHA1( )
Synopsis
SHA(string)
This function returns the SHA 160-bit checksum for the given string. The result is a string composed of 40 hexadecimal digits. NULL is returned if the given string is NULL. This function is synonymous with SHA( ).
Name
SYSTEM_USER( )
Synopsis
SYSTEM_USER( )
This function returns the username and the hostname for the current MySQL connection. The function takes no arguments. It’s synonymous with SESSION_USER( ) and USER( ).
Name
USER( )
Synopsis
USER( )
This function returns the username and the hostname for the current MySQL connection. The function takes no arguments. It’s synonymous with SESSION_USER( ) and withSYSTEM_USER( ). Here is an example:
SELECT USER( );
+-------------------+
| USER( ) |
+-------------------+
| russell@localhost |
+-------------------+
Chapter 5. Database and Table Schema Statements
This chapter explains the SQL statements in MySQL related to database and table schema. These statements create, alter, and delete databases and tables, as well as display information related to databases, tables, and columns. The statements in this chapter pertain to information about these data structures, not the manipulation of data within them; statements that affect the data are covered in the next chapter. In essence, this chapter covers the SQL statements used when one is in the mode of creating database structures. This mode is a fairly distinct mindset and is sometimes the responsibility of different persons from those who manipulate the data itself.
This chapter covers the following SQL statements:
ALTER DATABASE, ALTER SCHEMA, ALTER SERVER, ALTER TABLE, ALTER VIEW, CREATE DATABASE, CREATE INDEX, CREATE SCHEMA, CREATE SERVER, CREATE TABLE, CREATE