The mapping file for a new single-byte client character set, which the user creates, should contain up to four translation tables, analogous to the translation tables in DBC.CharTranslationV.
- The first table defines the translation from the single-byte transitional form to the double-byte Unicode form.
- The second table defines the translation from the single-byte transitional form to the corresponding uppercase double-byte Unicode form.
Only characters that are mapped differently from the first table should be included.
- The third table is optional, and allows for the user to create a many-to-one mapping from Unicode to the external character set if desired.
If the third table is not present, then an inverse mapping is computed from the translation defined in the first table.
- The fourth table defines the translation from double-byte Unicode form to the corresponding upper case single-byte internal transitional form. Only characters that are mapped differently from the optional third table (or the inverse mapping computed from the first table if the third table is not present) should be included.