Oracle PL/SQL Programming, Third Edition

Name

TO_NCHAR

Synopsis

TO_NCHAR is an overloaded function that can be used to convert either numbers, dates, or character strings to character strings in the national character set. The two TO_NCHAR functions (one for numbers, one for dates) work just like the TO_CHAR function described in Chapter 9. The one difference is that the return value is an NVARCHAR2 rather than a VARCHAR2.

This version of TO_NCHAR converts database character set data into its national character set equivalent. TO_NCHAR is the opposite of TO_CHAR, which is described in the previous section. The specification of TO_NCHAR is as follows:

FUNCTION TO_NCHAR(char_data IN VARCHAR2) RETURN NVARCHAR2

TO_NCHAR can accept any of the following types as input: CHAR, VARCHAR2, CLOB, and NCLOB. The return type is always NVARCHAR2.

Following is an example of TO_NCHAR’s translating a string from the database character set into the national character set:

DECLARE 
   a VARCHAR2(30) := 'Corner? What corner?';
   b NVARCHAR2(30);
BEGIN
   b := TO_NCHAR(a);
END;

If you’re planning to use TO_NCHAR, you should also review the use of TRANSLATE...USING, described earlier. Also be aware that TO_NCHAR may be used in the same manner as TO_CHAR to convert dates, times, and numbers into human-readable form. Such uses are described in Chapter 9 and Chapter 10.