What is the difference between char and varchar data types?
The char is a fixed-length character data type, the varchar is
a variable-length character data type.
Because char is a fixed-length data type, the
storage size of the char value is equal to the maximum size for this
column. Because varchar is a variable-length data type,
the storage size of the varchar value is the actual length of the
data entered, not the maximum size for this column.
You can use char when the data entries in a column are expected
to be the same size.
You can use varchar when the data entries in a column are expected
to vary considerably in size.