MySQL

MySQL

220px
Developer(s)	MySQL AB (before 2008), Sun Microsystems (2008-2010), Oracle (since 2010)
Initial release	May 23, 1995 (1995-05-23)
Repository	{{#property:P1324}}
Written in	C and C++
Operating system	Crossplatform
Type	RDBMS (embedded)
License	GNU GPL
Website	www.mysql.com

MySQL — free relational database control system.

General

MySQL is a client-server system for controlling multithread SQL-server, that provides support of various computational database machines, various client-side applications and libraries, tools for administrations and wide range of API.

Capabilities

Characteristics and portability

• Written on C and C++. Tested on various compilers.
• Cross-platform.
• API for C, C++, Eiffel, Java, Perl, PHP, Python, Ruby and Tcl.
• Multithreading takes advantages of core threds, i.e. MySQL able to work with multiple processors.
• Very fast tables based on B-trees with index compression.
• Very fast memory allocation based on thread system.
• Very fast connection based on one-sweep multi-join
• Lightning fast SQL-methods.
• MySQL-code tested with Purify and Valgrind

Column types

• Large amount: integer signed and unsigned, 1/2/3/4/8 byte-length, FLOAT, DOUBLE, CHAR, VARCHAR, TEXT, BLOB, DATE, TIME, DATETIME, TIMESTAMP, YEAR, SET and ENUM.
• Constant and variable length
• All columns have default values. INSERT provide ability to insert subset of columns.

Commands and functions

• Full support of methods and functions in SELECT- and WHERE- parts of request. For example:

mysql> SELECT CONCAT(first_name, " ", last_name)
     -> FROM tbl_name
     -> WHERE income/dependents > 10000 AND age > 30;

• Full support of SQL GROUP BY and ORDER BY with SQL-expressions.
• LEFT OUTER JOIN and RIGHT OUTER JOIN support with ANSI SQL and ODBC syntax.
• Aliases with respect to SQL92
• DELETE, INSERT, REPLACE, and UPDATE returns number of strings, that were changed. You can set it to return number of matched strings.
• Function names and table names are not conflicting
• In one request you can call different databases (since ver. 3.22).

Security

• System based on privileges and passwords. This provides flexibility and security with ability of remote verification. Passwords are encrypted.

Scalability and constraints

• Handle gigantic databases. (50 millions rows)
• Each table allowed to have 32 indexes. Each index contains from 1 to 16 columns. Maximum width of index: 500 bits. CHAR and VARCHAR prefixes are allowed.

Connection

• TCP/IP, unix sockets, named channels.
• Open-DataBase-Connectivity support.

Links

• Wiki