REQIF12 — AttributeDefinition should allow mutliplicities for attribute values

Section 10.3 says: "What is actually shared among the requirements is the requirement attribute definitions (the number of attributes, the names of the attributes, the default values for the attributes, and the datatypes of the attributes.)"

However, there is no possibility to allow more than one value for an attribute of a SpecType. This is a very fundamental conecept and should be provided by ReqIF 1.1.

A potential solution might be the following:

• Add a metaattribute upperValueBoundary to AttributeDefinition with default set to 1 (meaning, the attribute is allowed to have exactly one entry).

• Add two more metaattributes to AttributeDefinition: isOrdered:Boolean = true and isUnique:Boolean = true to enable the user specifying the nature of a list of attribute values

• Add a constraint to AttributeValue that ensures that the upperValueBoundary of the corresponding AttributeDefinition must be respected by an implementation

Take the issue out of scope, as it is a breaking change

Implementing this issue would introduce a change to the ReqIF XML schema.
This change to the XML schema would make ReqIF files that are valid against
the new XML schema incompatible with previous ReqIF files, thus breaking
interoperability with almost all tools that are on the market now (including
tools by IBM, PTC, NoMagic and many others).

As this is considered a major change, it should be taken out of scope for a RTF.