The elementary data type STRING is similar to data type
C and refers to a variable-length string. Accordingly, the elementary data type XSTRING is similar to data type X and refers to a variable-length byte sequence.
In contrast to a C or X field, the length of a string is not static but variable and adjusts itself
to the current field content at runtime. Dynamic memory management is used internally. Strings can have any length.
The initial value of a string is an empty string with length 0. A structure containing a string is seen
as deep. A deep structure cannot be used like a C field. Strings can be displayed in the ABAP Debugger and used in the ABAP Dictionary.
It is not yet possible to use strings in screens or database tables. However, strings can be stored in database tables as clusters using EXPORT and transferred using IMPORT.