Naming Conventions › Constraints on Naming Conventions › For Formats

For Formats

When used to name OS/400 database and device file formats, the components of the naming convention are:

• Format type (F MMMMPP): F identifies the format type:

  

For example, customer database file format: @CUDAXC, displays customers display file format: @DSCU##.

• Format mnemonic (F MMMM PP): MMMM is a mnemonic constructed according to the rules described in the next section.
• Format identifier (FMMMM II): II is a unique two-character format ID.

The format identifier for a physical file format should be unique to that file throughout the application, and preferably, the system.

The following values are reserved:

Device files should use a format identifier of #n for display devices and $n for printer devices. The identifier #Q is reserved for message subfiles. The format identifier need not be shown on the actual format names of device files, since you may want to use names that emphasize the role of the formats within a standard program type. Such formats will be few in number and should be named using the OS/400 naming principles, but the names should still begin with a character to indicate the format type. For example:

Give the format identifiers of database files letter combinations that do not usually occur in English; for instance JX, QP, ZW, as it is then easier to scan for a field with SEU’s scan facilities and be certain of a unique match.