Logical/Physical File Relationship

A file defined in PROIV is called a logical file while the file or database that is known to the operating system is called a physical file.

When you are creating a new file you are prompted for the File Name (which is mandatory and refers to the logical file) and the Physical File name (which is optional and refers to the physical file).

The relationship between logical files and physical files can be One-to-one or One-to-one with Aliasing.

One-to-One

The File Name is specified but no Physical File name. The logical file and the physical file are created with the same name (except that the physical file name usually has a .PRO extension).

One-to-One With Aliasing

Both the File Name and Physical File name are specified and the files are crated with their appropriate name.

By assigning the same Physical File name to multiple logical File Names you can have any number of aliases.

One-to-One files are used primarily in a production environment where file requirements are known. Important advantages are space efficiency, ease of access, and backup by non-PROIV systems.

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Topic ID: 730013