Coding Standards for Database Files › Physical and Logical Database Files › Field Level

Field Level

All fields should be defined by reference to the field reference file.

Field names should be issued according to the CA 2E Systematic naming convention cited at the beginning of this manual.

Use the DDS COLHDG keyword to define the descriptions for all fields. Make use of lower case. The descriptions you place on the field will be used in many places; for example, DFUs, queries, and documentation, so it is worth making them as "cosmetic" as possible.

Pack all numeric fields. The IBM midrange HLLs handle packed numeric fields more efficiently than zoned numeric fields. Note, however, that you cannot use the sub string function on packed numeric fields.

Make fields that hold text descriptions an even length, and specify a W shift. This ensures they can be used for ideographic translations without the truncation of ideographic shifts.

Include, as the last part of the COLHDG information, the abbreviation, in brackets, for the dimension of the field (for example, the units in which the field is held) or, if it has restricted values, the permitted values. For example:

The following are standard abbreviations for units: