Group qualified inverse attributes?

[Phil Spiby]

Expressarios,

The ballot comment NSF2 from Norway (given below) was accepted.

NSF2: In TC2 a restriction has been introduced concerning valid types
for INVERSE: "The name of the explicit attribute in the entity defining
the direct relationship shall be unique within the subtype/supertype
graph of that entity." This restriction is an unnecessary limitation.
The attribute could easily be qualified to the correct attribute by the
name of the supertype using a group qualifier.
ACCEPTED: Will need to introduce new syntax for inverse attributes to
allow such qualification, i.e. inverse inv: sub for sup1/attrib

On verifying this syntax change I have noticed that the comment and the
accepted resolution were wrong. It is not possible to use a group
qualifier in this way. According to EXPRESS the identifier after a group
qualifier shall be the name of an entity, in the case of the accepted
resolution an attribute identifier is given after the group qualifier. I
guess we could change the accepted resolution to allow a attribute
qualifier and have:
INVERSE
  inv : sub FOR sup1.attrib;

Suggestions etc.

Phil.

PS The reason for this comment was because TC2 had explicitly banned
inverses to ambiguous attribute identifiers (This I think was a good
move but other obviously didn't!). This resolution was an attempt to
allow these references again, but this time to ensure there was no
ambiguity by de-referencing the attribute identifier in the context of
the entity in which it was declared.