Adaptive Server version 15.7 allows you to create nonmaterialized, non-NULL columns.
Nonmaterialized columns exist virtually, but are not physically stored in the row. Use nonmaterialized columns the same as any other column, selecting, updating, and referring to them in SQL queries, or using them as index keys.
Adaptive Server treats nonmaterialized columns similar to the way it treats null columns: if a column is not physically present in the row, Adaptive Server supplies a default. The default for a nullable column is null, but the default for a nonmaterialized column is a user-defined non-NULL value.
See "Adding, Changing, Transferring, and Deleting Data" in the Transact-SQL Users Guide.