decompose takes as its argument a string in any datatype
and returns a Unicode string after decomposition in the same character
set as the input. For example, an o-umlaut codepoint will be returned as
the &o& codepoint followed by an umlaut codepoint.
- string can be any of the datatypes 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.
- 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.
decompose is valid only for Unicode characters.