Value Domain
Contents |
Format
A value domain specifies a specific set of values used to represent something/someone. These are the rules that apply to
The following graphic illustrates the structure of a domain.
<nowiki>*Classification scheme does not apply to all value domains</nowiki>
Rules about Value Domains
- A value title shall occupy the leftmost position of a value domain name where it is necessary to distinguish the value domain name from other metadata items.
- The representation class term shall follow the value title.
- The representation class term is qualified by the classification scheme term where the value domain implements a classification scheme.
- The unit of measure term shall follow where the value domain is of representation class average or total and this unit of measure is not implied by any other name component.
- The format term shall occupy the rightmost position of a value domain name.
- If any term in the value domain name is made redundant either explicitly through the duplication of a word, or implicitly through another word or phrase, delete one occurrence.
Sample Value Domains
| Value | Value character range |
|---|---|
| A | Alphabetic character set: contains the letters a-z and A-Z and may contain special characters**, but not numeric characters. |
| N | Numeric character set: contains whole and decimal numbers and may contain special characters, but not alphabetic characters. |
| X | Alphanumeric character set: contains alphabetic and numeric characters, and may contain blank characters. |
| D | A numeric character representing a number of days.* |
| M | A numeric character representing a number of months.* |
| Y | A numeric character representing a number of years.* |
| h | Any numeric character representing a number of hours.* |
| m | Any numeric character representing a number of minutes.* |
| s | Any numeric character representing number of seconds.* |
| { } | The string within the curly brackets (braces) is optional in its entirety (e.g. X{XX} indicates 1 or 3 alphanumeric characters (i.e. X or XXX)). |
| [ ] | The string within the square brackets is optional in any ordered combination (e.g. [XXX] indicates 0, 1, 2 or 3 alphanumeric characters (i.e. blank, X, XX or XXX)). |
| ( ) | The character preceding the round brackets (parentheses) is repeated the number of times specified (e.g. X(9) indicates 9 alphanumeric characters). |
Sample Data Elements and their associated value domains
<pre>E.g. #1 Person—tobacco smoking start age (daily smoking), total years NN
Definition: The age in years at which a person who has ever been a daily
smoker,first started to smoke daily.
E.g. #2 Person-activity and participation life area, code (ICF 2001) AN[NN]
Definition: The life area in which a person participates or
undertakes activities, as represented by a code. </pre>
| Definition # | Representation | Classification scheme | Unit of measure term | Format term |
|---|---|---|---|---|
| Definition #1 | Total | Does not apply | Year | NN |
| Definition #2 | Code | International Classification of Functioning, Disability and Health 2001 | Does not apply | ANN[NNN] |
Representation Class
The representation class reflects the main structure of the value domain A value domain that is of representation class Ratio consists of measures of at least two distinct concepts, each of which may be collected in its own right e.g. body mass index is calculated from measures of a person’s body weight and body height. In contrast, a value domain that is of representation class Total is either an absolute count of something, reported in one or more units (e.g. Australian currency), or one measure, expressed as a proportionate quantity (e.g. milligrams per litre).
| Value | Meaning |
|---|---|
| Average | A numeric value representing an arithmetic mean. |
| Code | A system of valid symbols that substitute for longer values. |
| Date | A numeric value representing a calendar date (i.e. day, month and year) or recognised part of a calendar date (i.e. day, month, and/or year). |
| Identifier | A value which establishes identity. |
| Percentage | Parts per hundred. |
| Ratio | An expression of the quantity of one substance or entity in relation to that of another (Dorlands, 2003: 1586). |
| Text | An unformatted, descriptive value. |
| Total | A numeric value representing the sum of a set of values or an entire quantity (including monetary). |
| Count | A numeric value representing a non-monetary numeric value arrived at by counting. |
| Currency | A numeric value representing a monetary value. |
| Quantity | A numeric value representing a continuous number such as the linear dimensions, capacity/amount (non-monetary) of an object. |
**A special character is a character which has a visual representation and is neither a letter, number, ideogram,or blank. For example, punctuation marks and mathematical symbols.
An ideogram is a character that represents an object or concept e.g. Chinese ideogram or Japanese Kanji.
A blank is a character that represents an empty position in an alphanumeric character field e.g. space. A blank is conceptually different from a null value, which is defined as the absence of a stored value.
* Valid in value domains of representation class Date or Time only. These format values indicate the valid unit(s) of measure to be presented. For value domains of all other representation classes, only the characters A, N, X, { }, [ ], and ( ) may be used to denote the presence of a value.
A set of attributes describing representational characteristics of instance data with or without enumerated permissible values.
