# description
This MessageHeader has been constrained to represent a message header for an event message, to support the Events Management Service project.

# snapshot.element[].short
A resource that describes a message that is exchanged between systems

# snapshot.element[].definition
The header for a message exchange that is either requesting or responding to an action.  The reference(s) that are the subject of the action as well as other information related to the action are typically transmitted in a bundle in which the MessageHeader resource instance is the first resource in the bundle.

# snapshot.element[].constraint[].human
If the resource is contained in another resource, it SHALL NOT contain nested Resources

# snapshot.element[].constraint[].human
If the resource is contained in another resource, it SHALL NOT contain any narrative

# snapshot.element[].constraint[].human
If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated

# snapshot.element[].constraint[].human
If the resource is contained in another resource, it SHALL be referred to from elsewhere in the resource

# snapshot.element[].definition
The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.

# snapshot.element[].comment
The only time that a resource does not have an id is when it is being submitted to the server using a create operation.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content may not always be associated with version changes to the resource.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
A set of rules under which this content was created

# snapshot.element[].definition
A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content.

# snapshot.element[].comment
Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element.   This element is labelled as a modifier because the implicit rules may provide additional knowledge about the resource that modifies it's meaning or interpretation.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The base language in which the resource is written.

# snapshot.element[].comment
Language is provided to support indexing and accessibility (typically, services such as text to speech use the language tag). The html language tag in the narrative applies  to the narrative. The language tag on the resource may be used to specify the language of other presentations generated from the data in the resource  Not all the content has to be in the base language. The Resource.language should not be assumed to apply to the narrative automatically. If a language is specified, it should it also be specified on the div element in the html (see rules in HTML5 for information about the relationship between xml:lang and the html lang attribute).

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Text summary of the resource, for human interpretation

# snapshot.element[].definition
A human-readable narrative that contains a summary of the resource, and may be used to represent the content of the resource to a human. The narrative need not encode all the structured data, but is required to contain sufficient detail to make it "clinically safe" for a human to just read the narrative. Resource definitions may define what content should be represented in the narrative to ensure clinical safety.

# snapshot.element[].comment
Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative. In some cases, a resource may only have text with little or no additional discrete data (as long as all minOccurs=1 elements are satisfied).  This may be necessary for data from legacy systems where information is captured as a "text blob" or where text is additionally entered raw or narrated and encoded in formation is added later.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
These resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently, and nor can they have their own independent transaction scope.

# snapshot.element[].comment
This should never be done when the content can be identified properly, as once identification is lost, it is extremely difficult (and context dependent) to restore it again.

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the resource. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
The type of event applicable to the event message

# snapshot.element[].definition
The type of event applicable to the event message.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the resource, and that modifies the understanding of the element that contains it. Usually modifier elements provide negation or qualification. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Code for the event this message represents

# snapshot.element[].definition
Code that identifies the event this message represents and connects it with its definition. Events defined as part of the FHIR specification have the system value "http://hl7.org/fhir/message-events".

# snapshot.element[].comment
Codes may be defined very casually in enumerations or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information.

# snapshot.element[].requirements
Drives the behavior associated with this message.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CE/CNE/CWE subset one of the sets of component 1-3 or 4-6

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The identification of the code system that defines the meaning of the symbol in the code.

# snapshot.element[].comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...).  OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should de-reference to some definition that establish the system clearly and unambiguously.

# snapshot.element[].requirements
Need to be unambiguous about the source of the definition of the symbol.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured. and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

# snapshot.element[].comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to refer to a particular code in the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A representation of the meaning of the code in the system, following the rules of the system.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know  the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.2 - but note this is not well followed

# snapshot.element[].short
If this coding was chosen directly by the user

# snapshot.element[].definition
Indicates that this coding was chosen by a user directly - i.e. off a pick list of available items (codes or displays).

# snapshot.element[].comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

# snapshot.element[].requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
fhir:Coding.userSelected fhir:mapsTo dt:CDCoding.codingRationale. fhir:Coding.userSelected fhir:hasMap fhir:Coding.userSelected.map. fhir:Coding.userSelected.map a fhir:Map;   fhir:target dt:CDCoding.codingRationale. fhir:Coding.userSelected\#true a [     fhir:source "true";     fhir:target dt:CDCoding.codingRationale\#O   ]

# snapshot.element[].definition
The destination application which the message is intended for.

# snapshot.element[].comment
There SHOULD be at least one destination, but in some circumstances, the source system is unaware of any particular destination system.

# snapshot.element[].requirements
Indicates where message is to be sent for routing purposes.  Allows verification of "am I the intended recipient".

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element, and that modifies the understanding of the element that contains it. Usually modifier elements provide negation or qualification. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
Human-readable name for the target system.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
May be used for routing of response and/or to support audit.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Particular delivery destination within the destination

# snapshot.element[].definition
Identifies the target end system in situations where the initial message transmission is to an intermediary system.

# snapshot.element[].comment
References SHALL be a reference to an actual FHIR resource, and SHALL be resolveable (allowing for access control, temporary unavailability, etc). Resolution can be either by retrieval from the URL, or, where applicable by resource type, by treating an absolute reference as a canonical URL and looking it up in a local registry/repository.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
Indicates where the message should be routed to.

# snapshot.element[].comment
The id may be a non-resolvable URI for systems that do not use standard network-based addresses.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Intended "real-world" recipient for the data

# snapshot.element[].definition
Allows data conveyed by a message to be addressed to a particular person or department when routing to a specific application isn't sufficient.

# snapshot.element[].comment
References SHALL be a reference to an actual FHIR resource, and SHALL be resolveable (allowing for access control, temporary unavailability, etc). Resolution can be either by retrieval from the URL, or, where applicable by resource type, by treating an absolute reference as a canonical URL and looking it up in a local registry/repository.

# snapshot.element[].requirements
Allows routing beyond just the application level.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].mapping[].map
Not directly supported.  Could be shared using attentionLine.value with an appropriate keyWordText

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
Identifies the sending system to allow the use of a trust relationship.

# snapshot.element[].comment
Use case is for where a (trusted) sending system is responsible for multiple organizations, and therefore cannot differentiate based on source endpoint / authentication alone.

# snapshot.element[].requirements
Allows routing beyond just the application level.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].mapping[].map
Not directly supported.  Could be shared using attentionLine.value with an appropriate keyWordText

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].comment
Note: This is intended for precisely observed times, typically system logs etc., and not human-reported times - for them, see date and dateTime below. Time zone is always required

# snapshot.element[].requirements
Allows limited detection of out-of-order and delayed transmission.  Also supports audit.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The person or device that performed the data entry leading to this message. When there is more than one candidate, pick the most proximal to the message. Can provide other enterers in extensions.

# snapshot.element[].comment
Usually only for the request, but can be used in a response.

# snapshot.element[].requirements
Need to know for audit/traceback requirements and possibly for authorization.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].mapping[].map
EVN-5 / ORC-10 / PRT-5:PRT-4='EP' / ROL where ROL.3 is EP or ORC.10

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The logical author of the message - the person or device that decided the described event should happen. When there is more than one candidate, pick the most proximal to the MessageHeader. Can provide other authors in extensions.

# snapshot.element[].comment
Usually only for the request, but can be used in a response.

# snapshot.element[].requirements
Need to know for audit/traceback requirements and possibly for authorization.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].mapping[].map
ORC-19 / PRT-5:PRT-4='AUT' / ROL where ROL.3 is IP or ORC.12

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The source application from which this message originated.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element, and that modifies the understanding of the element that contains it. Usually modifier elements provide negation or qualification. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
Human-readable name for the source system.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
May include configuration or other information useful in debugging.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Supports audit and possibly interface engine behavior.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
Can convey versions of multiple systems in situations where a message passes through multiple hands.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Supports audit and possibly interface engine behavior.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
An e-mail, phone, website or other contact point to use to resolve issues with message communications.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
A system is required if a value is provided.

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
phone | fax | email | pager | url | sms | other

# snapshot.element[].definition
Telecommunications form for contact point - what communications system is required to make use of the contact.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].binding.description
Telecommunications form for contact point

# snapshot.element[].definition
The actual contact point details, in a form that is meaningful to the designated communication system (i.e. phone number or email address).

# snapshot.element[].comment
Additional text data such as phone extension numbers, or notes about use of the contact are sometimes included in the value.

# snapshot.element[].requirements
Need to support legacy numbers that are not in a tightly controlled format.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
home | work | temp | old | mobile - purpose of this contact point

# snapshot.element[].definition
Identifies the purpose for the contact point.

# snapshot.element[].comment
This is labeled as "Is Modifier" because applications should not mistake a temporary or old contact etc.for a current/permanent one. Applications can assume that a contact is current unless it explicitly says that it is temporary or old.

# snapshot.element[].requirements
Need to track the way a person uses this contact, so a user can choose which is appropriate for their purpose.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Specify preferred order of use (1 = highest)

# snapshot.element[].definition
Specifies a preferred order in which to use a set of contacts. Contacts are ranked with lower values coming before higher values.

# snapshot.element[].comment
Note that rank does not necessarily follow the order in which the contacts are represented in the instance.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Time period when the contact point was/is in use

# snapshot.element[].definition
Time period when the contact point was/is in use.

# snapshot.element[].comment
This is not a duration - that's a measure of time (a separate type), but a duration that occurs at a fixed value of time. A Period specifies a range of time; the context of use will specify whether the entire range applies (e.g. "the patient was an inpatient of the hospital for this time range") or one value from the range applies (e.g. "give to the patient between these two times"). If duration is required, specify the type as Interval|Duration.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
If present, start SHALL have a lower value than end

# snapshot.element[].constraint[].expression
start.empty() or end.empty() or (start <= end)

# snapshot.element[].mapping[].map
IVL<TS>[lowClosed="true" and highClosed="true"] or URG<TS>[lowClosed="true" and highClosed="true"]

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The start of the period. The boundary is inclusive.

# snapshot.element[].comment
If the low element is missing, the meaning is that the low boundary is not known.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
End time with inclusive boundary, if not ongoing

# snapshot.element[].definition
The end of the period. If the end of the period is missing, it means that the period is ongoing. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time.

# snapshot.element[].comment
The high value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has a end value of 2012-02-03.

# snapshot.element[].meaningWhenMissing
If the end of the period is missing, it means that the period is ongoing

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
Identifies the routing target to send acknowledgements to.

# snapshot.element[].comment
The id may be a non-resolvable URI for systems that do not use standard network-based addresses.

# snapshot.element[].requirements
Identifies where to send responses, may influence security permissions.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The person or organization that accepts overall responsibility for the contents of the message. The implication is that the message event happened under the policies of the responsible party.

# snapshot.element[].comment
Usually only for the request, but can be used in a response.

# snapshot.element[].requirements
Need to know for audit/traceback requirements and possibly for authorization.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
Coded indication of the cause for the event - indicates  a reason for the occurrence of the event that is a focus of this message.

# snapshot.element[].comment
Not all terminology uses fit this general pattern. In some cases, models should not use CodeableConcept and use Coding directly and provide their own structure for managing text, codings, translations and the relationship between elements and pre- and post-coordination.

# snapshot.element[].requirements
Need to be able to track why resources are being changed and report in the audit log/history of the resource.  May affect authorization.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
EVN.4 / ORC.16 / OBR-31-reason for study / BPO-13-BP indication for use / RXO-20-indication / RXE-27-give indication / RXD-21-indication / RXG-22-indication / RXA-19-indication

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
A reference to a code defined by a terminology system.

# snapshot.element[].comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information.  Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

# snapshot.element[].requirements
Allows for translations and alternate encodings within a code system.  Also supports communication of the same instance to systems requiring different encodings.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CE/CNE/CWE subset one of the sets of component 1-3 or 4-6

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The identification of the code system that defines the meaning of the symbol in the code.

# snapshot.element[].comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...).  OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should de-reference to some definition that establish the system clearly and unambiguously.

# snapshot.element[].requirements
Need to be unambiguous about the source of the definition of the symbol.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured. and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

# snapshot.element[].comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to refer to a particular code in the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A representation of the meaning of the code in the system, following the rules of the system.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know  the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.2 - but note this is not well followed

# snapshot.element[].short
If this coding was chosen directly by the user

# snapshot.element[].definition
Indicates that this coding was chosen by a user directly - i.e. off a pick list of available items (codes or displays).

# snapshot.element[].comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

# snapshot.element[].requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
fhir:Coding.userSelected fhir:mapsTo dt:CDCoding.codingRationale. fhir:Coding.userSelected fhir:hasMap fhir:Coding.userSelected.map. fhir:Coding.userSelected.map a fhir:Map;   fhir:target dt:CDCoding.codingRationale. fhir:Coding.userSelected\#true a [     fhir:source "true";     fhir:target dt:CDCoding.codingRationale\#O   ]

# snapshot.element[].short
Plain text representation of the concept

# snapshot.element[].definition
A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

# snapshot.element[].comment
Very often the text is the same as a displayName of one of the codings.

# snapshot.element[].requirements
The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.9. But note many systems use C*E.2 for this

# snapshot.element[].definition
Information about the message that this message is a response to.  Only present if this message is a response.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element, and that modifies the understanding of the element that contains it. Usually modifier elements provide negation or qualification. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The MessageHeader.id of the message to which this message is a response.

# snapshot.element[].requirements
Allows receiver to know what message is being responded to.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
Code that identifies the type of response to the message - whether it was successful or not, and whether it should be resent or not.

# snapshot.element[].comment
This is a generic response to the request message. Specific data for the response will be found in MessageHeader.focus.

# snapshot.element[].requirements
Allows the sender of the acknowledge message to know if the request was successful or if action is needed.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
Full details of any issues found in the message.

# snapshot.element[].comment
This SHALL be contained in the bundle. If any of the issues are errors, the response code SHALL be an error.

# snapshot.element[].requirements
Allows the sender of the message to determine what the specific issues are.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The actual data of the message - a reference to the root/focus class of the event.

# snapshot.element[].comment
The data is defined where the transaction type is defined. The transaction data is always included in the bundle that is the full message.  Only the root resource is specified.  The resources it references should be contained in the bundle but are not also listed here.  Multiple repetitions are allowed to cater for merges and other situations with multiple focal targets.

# snapshot.element[].requirements
Every message event is about actual data, a single resource, that is identified in the definition of the event, and perhaps some or all linked resources.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())