[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]
Subject: Re: [plcs-dex] Implementer guidance
Although I tend to sympathize with Dave since I am doing practical implementations I find the whole issue confusing. If, in an actual implementation, we are to ignore all attributes except the ones that actually are to carry data (such as the id in Identification_assignment), then it is rather pointless to specify /IGNORE or whatever else. In effect, what the capability ends up saying is that "these few attributes carry real data, do what you please with the rest but under no circumstances should they be read". I can acept that argument, but it certainly goes against the current way the attributes are specified. My understanding is that currently a conforming implementation _must_ specify /IGNORE et al in the unused attributes. Otherwise we can simply state "fill in any random junk in the mandatory attributes, and leave the optional ones unset (if not, ignore them anyway when reading the file)". Regards, Per-Åke Tim Turner wrote: > > I have several thoughts about this. > > Dave has a point, although (at the risk of being contentious) if we are > to enforce this, should there not be Rules in each DEX's EXPRESS schema > to state that the relevant (entities') attribute value shall be "/IGNORE"? > > With respect to the earlier question, I have pasted the usage guidance > from PDM schema below. > Quote: > "* Empty string '' indicates user data managed by the sending system but > not provided for data exchange. > * String '/NULL' indicates user data in a mandatory attribute that is > not managed by the sending system or currently not known. > > * $ is used in the physical file, if an optional attribute is not > instantiated." > End Quote. > > > Adapting this I think that:- > > "/IGNORE" should be used where an optional attribute is instantiated as > reference data and reference data has been provided; > > "" the empty string, could be used where an optional attribute would be > instantiated as reference data, but none is provided (i.e. I have it but > will not provide it at present); > > "/NULL" could be used where an optional attribute would normally be > instantiated without reference data, but the value is either not managed > by the sending system or not currently known. > > Else, "$" could be used in a P21 file where an optional attribute is not > instantiated reference data and is not available in the reference data; > > Regards, > Tim > NB - all these situation revolve around the attributes of the ARM > entity. What about the case where there is NO attribute present in the > EXPRESS arm, but reference data is needed? > > > > > -----Original Message----- > From: Mike Ward [mailto:mike.ward@eurostep.com] > Sent: 16 January 2006 07:51 > To: 'David Price'; plcs-dex@lists.oasis-open.org > Subject: RE: [plcs-dex] Implementer guidance > > I tend to agree with Dave here. > > Another (albeit minor) consideration is that P28 data files can simply > miss out the elements corresponding to OPT attributes and the > distinction between /IGNORE and $ provides a handy way of reconciling > p21 and p28 files. > > Mike > > -- > > Dr Mike Ward > Eurostep Limited > 7 Dean Lane Head > Old Allen Road > Bradford > BD13 3RT > UK > tel: +44 1274 831187 > fax: +44 1274 831187 > mob: +44 7909 915976 > email: mailto:mike.ward@eurostep.com > url: www.eurostep.com > > Eurostep: open solutions, organization, and people. > > > All, > > Specifying /IGNORE is not useful to a post-processor at all as the > attribute value will never be read. Any DEX-based post-processor reading > the file will know to use Reference Data, not the explicit attribute. > So, you should simply leave it as $ as that takes less space and does > not require the pre-processor to set a value for every attribute > replaced by the use of Reference Data which can add noticable costs for > very large datasets. > > Cheers, > David > > --------- Original Message -------- > From: nigel.shaw@eurostep.com > To: plcs-dex@lists.oasis-open.org <plcs-dex@lists.oasis-open.org> > Subject: RE: [plcs-dex] Implementer guidance > Date: 16/01/06 09:07 > > > > > There are multiple possible interpretation of "$" whilst > > /IGNORE > has a > > defined meaning. Therefore send "/IGNORE" would be my > preference. > > > > As examples, "$" can be interpreted as "there is no > value", "I do not know > > the value", "I know the value but do not want to tell > > you", > "you are not > > allowed to know the value",... > > > > Nigel > > > > > > > > -----Original Message----- > > From: Barker, Sean (UK) [mailto:sean.barker@baesystems.com] > > Sent: 16 January 2006 08:47 > > To: plcs-dex@lists.oasis-open.org > > Subject: [plcs-dex] Implementer guidance > > > > > > > > I am resolving an issue on the implementer guidance for /IGNORE. > > > > Attribute values are set to '/IGNORE' when the information that could > > be held by the attribute will be instead assigned to the instance of > > the entity. Note: required attributes will always have an equivalent > > assigned, whereas optional attributes need not be assigned. > > > > While this describes how to populate instance diagrams, the question > arises, > > what happens in the physical file. That is, should an unpopulated > > optional attribute contain the value "$" or > > "/IGNORE"? > > > > > > Sean Barker > > 0117 302 8184 > > > > > > ******************************************************************** > > This email and any attachments are confidential to the intended > > recipient and may also be privileged. If you are not the intended > > recipient please delete it from your system and notify the sender. You > > should not copy it > or > > use it for any purpose nor disclose or distribute its contents to any > other > > person. > > ******************************************************************** > > > > > > > > > > > > > > ________________________________________________ > Message sent using UebiMiau 2.7.2 > > > > > *DISCLAIMER: ***SECURITY LABEL: NOT PROTECTIVELY MARKED*** The > information in this message is confidential and may be legally > privileged. It is intended solely for the addressee. Access to this > message by anyone else is unauthorised. If you are not the intended > recipient, any disclosure, copying, or distribution of the message, or > any action or omission taken by you in reliance on it, is prohibited and > may be unlawful. Please immediately contact the sender if you have > received this message in error. This e-mail originates from LSC Group. > Registered in England & Wales No 2275471 Registered Office: Devonport > Royal Dockyard, Devonport, Plymouth, PL1 4SG * > > -- ======================================================== Per-Åke Ling email: per-ake.ling_AT_eurostep.com .~. Eurostep AB mobile: +46 709 566 490 / v \ Vasagatan 38 http://www.eurostep.com /( _ )\ SE-111 20 Stockholm ^ ^
[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]