Oracle® Database SQL Language Reference 11g Release 2 (11.2) Part Number E17118-04 |
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DECOMPOSE
is valid only for Unicode characters. DECOMPOSE
takes as its argument a string in any data type and returns a Unicode string after decomposition in the same character set as the input. For example, an o-umlaut code point will be returned as the "o" code point followed by an umlaut code point.
string
can be any of the data types CHAR
, VARCHAR2
, NCHAR
, NVARCHAR2
, CLOB
, or NCLOB
.
CANONICAL
causes canonical decomposition, which allows recomposition (for example, with the COMPOSE
function) to the original string. This is the default and returns the string in NFD normal form.
COMPATIBILITY
causes decomposition in compatibility mode. In this mode, recomposition is not possible. This mode is useful, for example, when decomposing half-width and full-width katakana characters, where recomposition might not be desirable without external formatting or style information. It returns the string in NFKD normal form.
CLOB
and NCLOB
values are supported through implicit conversion. If char
is a character LOB value, then it is converted to a VARCHAR
value before the COMPOSE
operation. The operation will fail if the size of the LOB value exceeds the supported length of the VARCHAR
in the particular development environment.
See Also:
Oracle Database Globalization Support Guide for information on Unicode character sets and character semantics
The following example decomposes the string "Châteaux
" into its component code points:
SELECT DECOMPOSE ('Châteaux') FROM DUAL; DECOMPOSE --------- Cha^teaux
Note:
The results of this example can vary depending on the character set of your operating system.