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Oracle® Database SQL Reference 10g Release 2 (10.2) Part Number B14200-02 |
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# COMPOSE

Syntax

Description of the illustration compose.gif

Purpose

`COMPOSE` takes as its argument a string, or an expression that resolves to a string, in any datatype, and returns a Unicode string in its fully normalized form in the same character set as the input. `char` can be any of the datatypes `CHAR`, `VARCHAR2`, `NCHAR`, `NVARCHAR2`, `CLOB`, or `NCLOB`. For example, an `o` code point qualified by an umlaut code point will be returned as the o-umlaut code point.

`CLOB` and `NCLOB` values are supported through implicit conversion. If `char` is a character LOB value, 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

Examples

The following example returns the o-umlaut code point:

    SELECT COMPOSE ( 'o' || UNISTR('\0308') ) FROM DUAL;

    CO
    --
    ö

See Also: UNISTR