Application program can define a data format that is easy to handle in its own data processing. There are common data format like the word, literal data, zero terminated string,... A database application program may need to define more data types for itself. A DBCS character includes two bytes of data, if the first byte of DBCS character is not handled correctly, then some data may be lost during the processing. You can find the handling of a mixed SBCS and DBCS string in the String Manipulation.