A national character string is a sequence of bytes that
represents character data in UTF-8 or UTF16BE
encoding in a Unicode database.
The length of the string is the number of code units in the sequence. If the length
is zero, the value is called the empty string. This value should not
be confused with the null value.
National character strings
are synonyms for
character strings or graphic
strings.
Based on the value that is set
for nchar_mapping database configuration parameter,
national character strings are mapped as follows:- nchar_mapping is CHAR_CU32 in a Unicode database:
- NCHAR is a synonym for CHARACTER with string units CODEUNITS32
- NVARCHAR is a synonym for VARCHAR with string units CODEUNITS32
- NCLOB is a synonym for CLOB with string units CODEUNITS32
- nchar_mapping is GRAPHIC_CU32 in a Unicode
database:
- NCHAR is a synonym for GRAPHIC with string units CODEUNITS32
- NVARCHAR is a synonym for VARGRAPHIC with string units CODEUNITS32
- NCLOB is a synonym for DBCLOB with string units CODEUNITS32
- nchar_mapping is GRAPHIC_CU16 in a Unicode
database:
- NCHAR is a synonym for GRAPHIC with string units CODEUNITS16
- NVARCHAR is a synonym for VARGRAPHIC with string units CODEUNITS16
- NCLOB is a synonym for DBCLOB with string units CODEUNITS16
For details, refer to the topics "Character
strings" and "Graphic strings".
DB2 10.5 for Linux, UNIX, and Windows