Dev:Semantic Constraints: Difference between revisions

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Semantic constraints are even important as XSD constraints. If they are ignored, security issues may arise.
Semantic constraints are even important as XSD constraints. If they are ignored, security issues may arise.


Elements with semantic constraints are listed in [[:Category:Semantic constraint]]. On the element documentation pages the semantic constraints can be found in a dedicated chapter below the syntactic constraints.
Elements with approved semantic constraints are listed in [[:Category:Semantic constraints]]. On the element documentation pages, the semantic constraints can be found in a dedicated chapter below the syntactic constraints. Proposed semantic constraints are listed in [[:Category:Semantic constraints_proposed]]. A list of the introduction date of a semantic constraint can be found in the list below.
{{note|Semantic constraints that have been '''proposed before the 10th of December 2018''' shall be considered as '''approved''' until decided otherwise.}}


Every application of {{rml}} has to be checked not only on XML conformity but also on obediance of the semantic constraints.
Every application of {{rml}} has to be checked not only on XML conformity but also on the obedience of the semantic constraints.
==How to introduce Semantic Constraints==
Generally speaking, constraints should better be implemented syntactically in the schema. Please, follow the [[Dev:Guideline for participating in the development process|guideline for participating in the development process]].
 
If you see need for a ''semantic'' constraint beyond the schema, please discuss it in the {{site|https://www.railml.org/forum|forum}}. If there is consent, you may decide to add a proposal in the element documentation using [[Template:Semcon]]. Please, add the proposal to the list below! If the proposal is accepted, it will implemented in the wiki using [[Template:Semcon]].
==Current Constraints==
[[Dev:Semantic_Constraints/table|View/edit list on the separate source page]].
{{:Dev:Semantic_Constraints/table}}
 
[[Category:GeneralDescription]]

Revision as of 13:23, 9 July 2019

Semantic constraints

XSD offers a variety of possibilities to define constraints. However, in some rare exceptions it is not possible to express an important rule in XSD. Rules that do not fit into XSD have to be expressed by words, semantically.

Semantic constraints are even important as XSD constraints. If they are ignored, security issues may arise.

Elements with approved semantic constraints are listed in Category:Semantic constraints. On the element documentation pages, the semantic constraints can be found in a dedicated chapter below the syntactic constraints. Proposed semantic constraints are listed in Category:Semantic constraints_proposed. A list of the introduction date of a semantic constraint can be found in the list below.

🗒️ Semantic constraints that have been proposed before the 10th of December 2018 shall be considered as approved until decided otherwise.


Every application of railML® has to be checked not only on XML conformity but also on the obedience of the semantic constraints.

How to introduce Semantic Constraints

Generally speaking, constraints should better be implemented syntactically in the schema. Please, follow the guideline for participating in the development process.

If you see need for a semantic constraint beyond the schema, please discuss it in the forum (link to the railML® website). If there is consent, you may decide to add a proposal in the element documentation using Template:Semcon. Please, add the proposal to the list below! If the proposal is accepted, it will implemented in the wiki using Template:Semcon.

Current Constraints

View/edit list on the separate source page.

Element ID Proposal date Date of acception Date of deprecation Description
<TT:timetablePeriod> TT:001 2018-11-12 2019-03-21 Any starting time stamp (as it may result e.g. from a combination of startDate and startTime) shall be lower or equal any ending time stamp (e.g. endDate) if both are given. Must not overlap with other validity periods.
<TT:specialService> TT:001 2018-11-12 2019-03-21 Any starting time stamp (as it may result e.g. from a combination of startDate and startTime) shall be lower or equal any ending time stamp (e.g. endDate) if both are given. Must not overlap with other validity periods.
<TT:operatingPeriodRef> TT:001 2018-11-12 2019-03-21 Any starting time stamp (as it may result e.g. from a combination of startDate and startTime) shall be lower or equal any ending time stamp (e.g. endDate) if both are given. Must not overlap with other validity periods.
<TT:operatingPeriod> TT:001 2018-11-12 2019-03-21 Any starting time stamp (as it may result e.g. from a combination of startDate and startTime) shall be lower or equal any ending time stamp (e.g. endDate) if both are given. Must not overlap with other validity periods.
<TT:operatingDay> TT:001 2018-11-12 2019-03-21 Any starting time stamp (as it may result e.g. from a combination of startDate and startTime) shall be lower or equal any ending time stamp (e.g. endDate) if both are given. Must not overlap with other validity periods.
<TT:circulation> TT:001 2018-11-12 2019-03-21 Any starting time stamp (as it may result e.g. from a combination of startDate and startTime) shall be lower or equal any ending time stamp (e.g. endDate) if both are given. Must not overlap with other validity periods.
<TT:blockPart> TT:001 2018-11-12 2019-03-21 Any starting time stamp (as it may result e.g. from a combination of startDate and startTime) shall be lower or equal any ending time stamp (e.g. endDate) if both are given. Must not overlap with other validity periods.
<RS:designator> (introduced with version 2.5) TT:001 2018-11-12 2019-03-21 Any starting time stamp (as it may result e.g. from a combination of startDate and startTime) shall be lower or equal any ending time stamp (e.g. endDate) if both are given. Must not overlap with other validity periods.
<RS:operator> TT:001 2018-11-12 2019-03-21 Any starting time stamp (as it may result e.g. from a combination of startDate and startTime) shall be lower or equal any ending time stamp (e.g. endDate) if both are given. Must not overlap with other validity periods.
<RS:owner> (introduced with version 2.5) TT:001 2018-11-12 2019-03-21 Any starting time stamp (as it may result e.g. from a combination of startDate and startTime) shall be lower or equal any ending time stamp (e.g. endDate) if both are given. Must not overlap with other validity periods.
<RS:state> TT:001 2018-11-12 2019-03-21 Any starting time stamp (as it may result e.g. from a combination of startDate and startTime) shall be lower or equal any ending time stamp (e.g. endDate) if both are given. Must not overlap with other validity periods.
<IS:state> TT:001 2018-11-12 2019-03-21 Any starting time stamp (as it may result e.g. from a combination of startDate and startTime) shall be lower or equal any ending time stamp (e.g. endDate) if both are given. Must not overlap with other validity periods.
<IS:state (with length)> TT:001 2018-11-12 2019-03-21 Any starting time stamp (as it may result e.g. from a combination of startDate and startTime) shall be lower or equal any ending time stamp (e.g. endDate) if both are given. Must not overlap with other validity periods.
<IS:designator> TT:001 2018-11-12 2019-03-21 Any starting time stamp (as it may result e.g. from a combination of startDate and startTime) shall be lower or equal any ending time stamp (e.g. endDate) if both are given. Must not overlap with other validity periods.
<CO:designator> (introduced with version 2.5) TT:001 2018-11-12 2019-03-21 Any starting time stamp (as it may result e.g. from a combination of startDate and startTime) shall be lower or equal any ending time stamp (e.g. endDate) if both are given. Must not overlap with other validity periods.
<CO:phase> (introduced with version 2.5) TT:001 2018-11-12 2019-03-21 Any starting time stamp (as it may result e.g. from a combination of startDate and startTime) shall be lower or equal any ending time stamp (e.g. endDate) if both are given. Must not overlap with other validity periods.
<TT:ocpTT> TT:002 2018-10-25 2019-06-20 The attribute sequence is shall be increasing according to the train path.
<TT:ocpTT> 2018-10-25 discarded No ocpRef is allowed to occur more than one time in the same <trainPart>
<TT:blockPart> TT:003 2019-07-13 2019-07-18 By means of a <blockPart> it is possible to model both journeys with and without reference to a <trainPart> within a roster, as well as services without change of location (without reference to a <trainPart>). These 3 basic types are distinguished by the attribute mission. The following table presents the semantic constraints: (not included here)
<TT:blockPart> TT:004 2019-07-20 2019-07-18 vehicleRef and formationRef shall not be used within the same blockPart, since a blockPart is either one for a certain vehicle or one for a whole formation.
<TT:rostering> TT:005 2019-05-22 2019-06-25 vehicleRef and formationRef are to be used exceptional since the circulation plan is either one for a certain vehicle or one for a whole formation.
<TT:stopDescription> TT:006 2018-09-03 2019-06-20 Constraints between the attributes <ocpTT>.ocpType, <stopDescription>.guaranteedPass, .commercial, .onOff, .stopOnRequest and .operationalStopOrdered
<TT:stopDescription> (Stop on request / More than one stop type per OCP) TT:007 2019-06-19 discarded 2020-04-23
<TT:trackInfo> TT:008 2018-08-21 2019-06-20 The representation of differentiated track usage must not result in differences in arrival and departure times. In these cases, a separate <trainPart> / <train> with different arrival and departure times must be created.
<TT:trackInfo> TT:009 2018-08-21 2019-06-20 The operating days days of the <operatingPeriodRef>s of the individual <trackInfo> entries must be disjoint and must not contain more traffic days than the parent <trainPart>. If fewer traffic days are provided in the <trackInfo> entries than the parent <trainPart> contains, the information (e.g. attribute trackInfo) of the parent <ocpTT> must be evaluated for these operating days.
<TT:times> (Correct encoding of run time supplements) TT:010 2019-06-19 2020-10-15 @scope='earliest' and 'latest' are not intended to encode supplement times, as this is redundant to <ocpTT>.<sectionTT>.<runTimes>@operationalReserve, @additionalReserve, @minimalTime.
<TT:times> TT:011 2019-06-19 discarded
<TT:times> TT:012 2019-06-19 2022-06-02 When @scope='actual' is used, then the operating period and/or timetable period specified at the trainpart level shall refer to only one operating day. Like this the operating day to which the actual times refer is defined.
<TT:times> TT:013 2019-06-19 discarded
<TT:times> (Arrival times for passing OCP's) TT:014 2019-06-19 2022-06-02 @arrival is not to be specified if the attribute ocpType of the parent <ocpTT> has the value pass - use departure for run-through (passing) times; This is in line with the definition of @arrival as the moment at which the train ends its movement and gets to a halt at the parent <ocpTT>.
<TT:times> (Arrival time at first OCP) TT:015 2019-06-19 2022-06-02 At the first <ocpTT> of a <trainPart> that is not the first one of the <trainPartSequence>, the attribute @arrival is optional. If it is set anyway, then, for consistency reasons, the value of @arrival of the regarding <ocpTT> must be identical for both this <trainPart> and the preceding one.
<TT:times> (Departure time at last OCP) TT:016 2020-10-09 2022-06-02 At the last <ocpTT> of a <trainPart> that is not the last one of the <trainPartSequence>, the attribute @departure is optional. If it is set anyway, then, for consistency reasons, the value of @departure of the regarding <ocpTT> must be identical for both this <trainPart> and the subsequent one.
<TT:connection> TT:017 2022-12-15 2022-12-15 If the trainPartRef attribute is given, then there must also be a trainRef attribute, and the trainPartRef attribute must point to a train part of the train referenced by the trainRef attribute.
<IS:speedChange> IS:001 2019-04-11 discarded Always define trainRelation
<IS:trackEnd> IS:002 2019-06-17
<IS:trackBegin> IS:003 2019-06-17
<IS:track> IS:004 2019-06-17 Single track railway lines shall have main driving direction @mainDir="none" if they are used in both directions
<IS:ocp> IS:005 2019-06-19 2022-07-14 An <ocp> that refers to a parent <ocp> via an @parentOcpRef overwrites the attributes and elements of the parent <ocp> if explicitely defined. If an element is specified on an <ocp> that uses a @parentOcpRef any information provided with that element on a higher layer of the <ocp>-tree is overwritten. There is no merging of element-information from different levels. The same applies for attributes of <ocp>.
<IS:mileageChange> IS:006 2019-06-19
  • Define attributes @absPosIn and @absPos for "real" mileage changes
  • Define attribute @absPosIn alone in case of an ending mileage
  • Define attribute @absPos alone in case of a starting mileage
  • For starting mileages and "real" mileage changes, the @absDir has to be fiven to define the ongoing orientation of the mileage
<IS:propOperational> IS:007 2020-02-25 discarded
<IS:uptime> IS:008 2020-02-28 An <ocp> with <propOperational>@operationalType=blockSignal shall not have

@mode=manned (as a manned blockSignal shall be modelled in railML® 2.x as a blockPost).

<IS:uptime> IS:009 2020-02-28 An <ocp> with attribute <propOperational>@operationalType=stoppingPoint shall not have @mode=manned (as a stoppingPoint has no operational usage and therefore no operational staff by the IM).
<IS:uptime> IS:010 2020-02-28 An enumeration of several time periods by @from and @until for one <ocp> shall not overlap so that for every time there shall be a unique status of <uptime>.
<IS:speedChange> IS:011 2022-03-14 (to be def. more accurately) 2021-11-10 (40th conference slide 11)
  • Every <track> has to have at least one <speedChange> at the track begin with parameters @pos="0" and @dir="up".
  • Every <track> has to have at least one <speedChange> at the track end with parameters @pos="{value equal to trackEnd@pos}" and @dir="down".
<IS:speedProfile> IS:012 2022-03-14 @basicSpeedProfile is always linked with @influence=increasing
<IS:speedProfile> IS:013 2022-03-14
  • @influence=increasing: The <speedProfile> increases the permitted speed. If multiple "increasing" speed profiles are applicable, select the one with the highest @vMax value.
  • @influence=decreasing: The <speedProfile> decreases the permitted speed. If multiple "decreasing" speed profiles are applicable, select the one with the lowest @vMax value. If this value is lower than the speed of an "increasing" speed profile, it overrides that speed.
<IS:tunnel> IS:014 2022-03-14 Define the tunnel resistance factor @resistanceFactorPassenger resp. @resistanceFactorFreight only if @kind and @crossSection are not known.
<IS:ocp> IS:015 2022-07-14 2022-08-11 When specifying @parentOcpRef for an <ocp> circles are not allowed. That means that when following the chain of @parentOcpRef no <ocp> shall be visited twice.
<IS:axleWeightChange> <clearanceGaugeChange> <electrificationChange> <gaugeChange> <ownerChange> <gradientChange> <powerTransmissionChange> <radiusChange> IS:016 2021-11-10 2021-11-10 must not have @dir attribute according to Report from the Infrastructure developers in railML 3.2 and 2.5 (link to the railML® website) slide 9 and #357
<railml> <infrastructure> IS:017 2024-03-25 2021-03-25 either <infrastructure> or <railml> must have @version attribute
<metadata> @name IS:018 2024-03-25 2021-03-25 either <metadata> must have <dc:language> child or every @name attribute accompanied by @xml:lang
<IS:gradientChange> IS:019 2024-03-25 2021-03-25 there can be no two <gradientChange> belonging to the same track with the same @pos attribute