MySQL Reference Manual for version .

Go to the first, previous, next, last section, table of contents.

Character set used for data & sorting.

By default, MySQL will use the ISO8859-1 (Latin1) character set. This is the character set used in the USA and western Europe.

The character set decides what characters are allowed in names and how things are sorted by the ORDER BY and GROUP BY commands.

You may change this at compile time by the configure switch --with-charset=charset. See section Quick installation overview..

If you want to add another character set to MySQL you must:

Choose a name. CHARSET_NAME
Create the file mysql_source_directory/strings/ctype-$CHARSET_NAME.c.
Look at one of the existing ctype files to see what needs to be defined. Note that the arrays in this file must have names like ctype_$CHARSET_NAME, to_lower_$CHARSET_NAME and so on. tolower[] and toupper[] are simple arrays that holds the corresponding lower resp. upper character for each character. For example:
```
to_lower['A'] should contain 'a'
to_upper['a'] should contain 'A'
```
sort_order[] is a map of how characters should be sorted. For many sets this is the same as to_upper (case insensitive sorts). MySQL will sort characters based on the value of sort_order[character]. ctype[] is a array of bits that describes each character. You can find the following definitions in m_ctype.h:
```
#define _U      01      /* Upper case */
#define _L      02      /* Lower case */
#define _N      04      /* Numeral (digit) */
#define _S      010     /* Spacing character */
#define _P      020     /* Punctuation */
#define _C      040     /* Control character */
#define _B      0100    /* Blank */
#define _X      0200    /* heXadecimal digit */
```
For example ctype['A'] should contain the value: _U + _X = 0201
Add to include/m_ctype.h.in a unique number for the char set.
Add charset name to CHARSETS_AVAILABLE list in configure.in
Recompile and test

If you are making a multiple-character char set, you can use the _MB macros. In `strings/m_ctype.h.in' add:

#define MY_CHARSET_<C>		X
#if MY_CHARSET_CURRENT == MY_CHARSET_<C>
#define USE_MB
#define USE_MB_IDENT
#define ismbchar(p, end)	(...)
#define ismbhead(c)		(...)
#define mbcharlen(c)		(...)
#define MBMAXLEN		N
#endif

MY_CHARSET_<C>	unique value.
USE_MB	This charset have mb-char.
USE_MB_IDENT:	Use mb-char as identifier. (optional)
ismbchar(p, e)	return 0 if not mb-char, or size of char if mb-char. Check from (char)p to (char)e-1.
ismbhead(c)	Is c first char of mb or not?
mbcharlen(c)	Size of char if c is first char of mb.
MBMAXLEN	Maximum size of one character.

Go to the first, previous, next, last section, table of contents.