Issue 4148: PDM RTF issue: "successor" (pdm-rtf) Source: NIST (Mr. Edward J. Barkmeyer, edbark(at)nist.gov) Nature: Uncategorized Issue Severity: Summary: As documented in 2.4.3.20, Supersedes is a RevisionMaster relationship that represents the decision to "roll part number" in implementing a part revision. That is, it represents the replacement of a previous rev, e.g. 1234-C-1, with a new Part, e.g. 1255(-A-1). But the most common RevisionRelationship, also sometimes called "supersedes", is what happens when 1234-D replaces 1234-C. That relationship is actually modelled by the relationship called "successor" that is a documented subtype of "Derive" (2.4.3.17), and is a relationship between ItemIterations (which is correct). But the other subtypes of Derive ("copied" and "translated") have significantly different semantics, implying a continuing dependency on the original. Successor, especially as it relates to ECNs, does not implicitly have this property: 1234-D-3 may be the new baseline, successor to 1234-C-4. Successor should be an explicit subtype of IterationRelationship (at the same level of visibility as Dependency and Derive) in the PdmFramework. Note for the RTF: I am raising this as an issue to be discussed, but I'm not convinced we want to make a change. First, this change could be disruptive to existing implementations. Second, if you have a base part design pending approval and start a set of serial-number-specific variants of the base part (truly "derived" iterations) and the base part design is *not* approved and acquires a "successor", you want to retrofit the changes in the base part (the "successor") to the variants. And that is a "convenience function" that follows the "successor" relationship backward and then the transitive closure of the Derive relationships forward, including successor iterations of the derivative variants. I assume that is why the model works the way it does. It may be that the ECO/ECN "successor"/"supersedes" relationship is actually a *different* relationship! Resolution: Revised Text: Actions taken: January 11, 2001: received issue Discussion: The behavior requested is supported by the existing model, but discussion of standard traversals in v2 may identify the need for an explicit successor relationship at a higher level. End of Annotations:===== Date: Thu, 11 Jan 2001 13:02:08 -0500 From: Ed Barkmeyer Reply-To: edbark@cme.nist.gov Organization: NIST X-Sender: "Ed Barkmeyer" X-Mailer: Mozilla 4.51 [en]C-CCK-MCD (WinNT; I) X-Accept-Language: en,fr-FR,de-DE,nl,sv MIME-Version: 1.0 To: issues@omg.org, OMG PDM Enablers RTF CC: "Ted L. Briggs" , JPDM Subject: PDM RTF issue: "successor" Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii X-UIDL: BlJd9nF$!!