Prior to Release 8.0, ECLASS interpreted its value lists as open, i.e. as suggestions that were never intended to be exhaustive. As the ISO defines value lists as restrictive and exclusive ECLASS had to change its structure to be ISO-compliant. Therefore ECLASS now distinguishes between "restrictive value lists" (ISO view) and "suggested value lists" (proposed "open" lists that are not exhaustive). Because of this, most value that were noted until Release 6.2 are now marked as CLOSED as they are to be interpreted as restrictive. Correspondingly, all relations between properties and values in the context of a class listed in the value proposal file (eClass7_0_PR_VA_suggested_en_02.csv) are new, i.e. all relations listed in that file are interpreted as NEW and not published here again.
A value list has a unique identifier and describes the relation between a property and a value. A value list according to ISO 13584 is a set of restrictive values, i.e. lists of values that are complete and therefore only these values are valid for a property. In ECLASS, only the BOOLEAN list (comprising the values yes and no) and value lists that form a polymorphism are considered to be restrictive, because they are exhaustive and no other value is possible. This relation is therefore true in any given context.
How a value list can be requested in the ECLASSContentDevelopmentPlatform is described on the value list help page.
The description of a value list in the BASIC release notes is as follows (update: Release 8.0):
A suggested value list, also known as open value list, consists of suggested values, i.e. values that are proposals and are not restrictive. The exhaustiveness of these listed values cannot be guaranteed as more values might be valid in a certain context. E.g. for a property colour values can only be interpreted as being suggestions - more colours can always be possible. The suggested value list (having a unique IRDI itself) therefore describes the relation between a class, a property and a value, because in theory, a property can have different valid values in the context of different classes, see below constraint.
Suggested value lists can be restricted by a constraint in the context of a class. The constraint is assigned to the application class or an aspect and contains the information of a property and the suggested values in the property's value list.
I.e. the suggested value list is assigned to a property and can optionally be restricted in a specific class via a constraint. It is thereby turned into a class-specific value list.
- Property PRO123 has a value list VLI123 that contains the values [VAL001; VAL002, VAL003; VAL004].
- For class CCL001 only the following values are valid for PRO123: [VAL001; VAL002, VAL003]
- For class CCL002 only the following values are valid for PRO123: [VAL001; VAL002]
- For class CCL003 only the following value is valid for PRO123: [VAL004]
The description of a suggested value list including constraints in the BASIC release notes is as follows (update: Release 8.0):