Code validation (strict)

This code validation is stricter than the standard code validation.

Discussion

The primary reasons for creating codes are:

Short visual identification of an entity. The code does not need to fully describe the entity just to uniquely identify it.
Easily type the code in dropdown search fields.
When needed, easily write down the code.
Sort (order) the entities by different criteria.

Allowed characters

Under strict code validation, the code can only contain (in order of suggested usage):

Digits
Minus (-)
Uppercase letters (the English alphabet only)
Plus (+)

The following symbols are NOT allowed:

Space ( )
Dot (.)
Forward slash (/)
Backslash ()
Lowercase letters

The reasons for strict limiting of the code symbols are concatenation, parsing and processing of codes with more freedom.

Length

The default maximum length for code attributes is 16 characters. It is still recommended that codes be 5 characters or less.

Suggestions

When creating codes, there are some general rules:

Usage of digits is highly suggested.

Digits (and the minus sign) are universal and language-agnostic. They can be typed on any keyboard without switching language settings. They are also easier to memorize.

It is better to create short, consecutive code than a long, meaningful code (usually with several parts).
Usage of letters is generally not advised.
When letters are used, use uppercase English letters.
Keep codes short. Preferably 5 characters maximum.

Note

The human eye can immediately read codes up to 5 chars in length (78542).

Longer codes take more time (784521).

For a small (less than 20) number of items, meaningful, letter-only codes might be adequate. For example "ABC", "LIB", etc.
When creation of meaningful codes is unavoidable:

a. You can still use digits and keep the code type-able on a numeric keypad.
b. Separate the parts with a minus sign
c. Keep the length of each part less than 5 chars.
d. Keep the total length to minimum.