In a3790 or DPCX application program, a set of programming statements that define the contents and structure of a data unit by specifying pages, lines in pages, fields within lines, and items within fields.

• 在3790或分布式处理控制执行程序（DPCX）应用程序中，一组程序设计语句，它通过规定页、页中行、行中字段、字段中项的办法确定数据单元的内容和结构。