The CHAR[ACTER] data type defines an alphanumeric column. Specification of length attribute n is optional. If no other length attribute is specified, then n=1.
CHAR[ACTER] [(n)]: 0<n<=8000
CHAR[ACTER] [(n)] UNICODE: 0<n<=4000
The database system determines, in accordance with n, whether the values in the column are stored with a fixed or variable length. If you want to store the values in a variable length regardless of the value of n, you must use VARCHAR.