Declaration of graphic host variables in C and C++ embedded SQL applications
To handle graphic data
in C or C++ applications, you must use host variables based on either
the
wchar_t
C or C++ data type or the sqldbchar
data
type.
You can assign graphic data host variables to columns of a table that are GRAPHIC, VARGRAPHIC, or DBCLOB. For example, you can update or select DBCS data from GRAPHIC or VARGRAPHIC columns of a table.
There are three valid forms for a graphic host variable:
- Single-graphic form
Single-graphic host variables have an SQLTYPE of 468/469 that is equivalent to the GRAPHIC(1) SQL data type.
- Null-terminated graphic form
Null-terminated refers to the situation where all the bytes of the last character of the graphic string contain binary zeros ('\0's). They have an SQLTYPE of 400/401.
- VARGRAPHIC structured form
VARGRAPHIC structured host variables have an SQLTYPE of 464/465 if their length is between 1 and 16 336 bytes. They have an SQLTYPE of 472/473 if their length is between 2 000 and 16 350 bytes.