A
column's length refers to the number of bytes that are used to store each of the column's
values in a file. For example, a column that is defined as a DOUBLE has a storage
size of 8 bytes.
In SAS, you can control the length with the LENGTH statement in the DATA step. However,
the LIBNAME engine does not support specifying a shorter numeric storage size with
the LENGTH statement. When you use the engine, you can read a legacy
SAS file with a shorter numeric storage size, but you cannot specify a shorter numeric storage
size or update the data.