SAS
5 and SAS 6 data sets generally need to be migrated to SAS 9.2 to
enable you to use the I/O features introduced in SAS 9 and SAS 8.
For example, to add integrity constraints to a SAS 6 data set, you
must first migrate that data set to SAS 9.2. For information about
migrating your data sets, see the Migration focus area at
support.sas.com/migration.