It would be good to have a built-in HEX function, or another method to create character values with arbitrary ASCII values (e.g. TAB, CR/LF, etc.).
If "CHAR FOR BIT DATA" values could be converted to CHAR or VARCHAR, the x'...' syntax could be used to create binary character constants. But I found no way to convert "CHAR FOR BIT DATA" to CHAR.
I didn't find an explicit description of the X'...' syntax in the reference manual. The only 2 occurences are in the SQL examples of the LENGTH function ("VALUES LENGTH(X'FF')") and of the "CHAR FOR BIT DATA" data type ("INSERT INTO t VALUES (X'DE');"). Is the x'...' syntax an unwanted remains from an old Cloudscape version, or will it still be supported (and properly documeted) in future Derby versions?