You use the NCHAR datatype to store fixed-length (blank-padded if necessary) national character data. How the data is represented internally depends on the national character set specified when the database was created, which might use a variable-width encoding (UTF8) or a fixed-width encoding (AL16UTF16). Because this type can always accommodate multibyte characters, you can use it to hold any Unicode character data.
The NCHAR datatype takes an optional parameter that lets you specify a maximum size in characters. The syntax follows:
NCHAR[(maximum_size)]
Because the physical limit is 32767 bytes, the maximum value you can specify for the length is 32767/2 in the AL16UTF16 encoding, and 32767/3 in the UTF8 encoding.
You cannot use a symbolic constant or variable to specify the maximum size; you must use an integer literal.
If you do not specify a maximum size, it defaults to 1. The value always represents the number of characters, unlike CHAR which can be specified in either characters or bytes.
