An extended site-defined character set defines the mapping of hexadecimal values to characters for single- and multibyte components of a character set. If you use a non-Western European language such as Russian, Arabic, or Urdu, you can define and install your own single-byte character set. If you use a non-Western European language such as Japanese, Korean, or Chinese, and the Teradata-supplied character sets are not entirely sufficient for your site, you can define and install your own multibyte character set.
Extended site-defined character sets can support, with certain constraints, any subset of the Unicode repertoire.
A user who is sufficiently privileged can define the relevant client character set, mapping bytes from the client to their corresponding Unicode values.