Summary
Diagnostics
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General
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Other
Conformance
Documents
Terminology
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Medication Definition
Public Health & Research
Complex
Primitive
ActivityDefinition
CapabilityStatement
ChargeItemDefinition
Claim
CodeSystem
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CoverageEligibilityRequest
Encounter
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List
Measure
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MessageHeader
NamingSystem
Observation
Patient
PlanDefinition
Resource
StructureDefinition
StructureMap
ValueSet
default
Base StructureDefinition for ElementDefinition Type: Captures constraints on each element within the resource, profile, or extension.
ElementDefinition
Path
ElementDefinition
Id
ElementDefinition
Cardinality
0 - *
Definition
Captures constraints on each element within the resource, profile, or extension.
Comment
Constraint
eld-2 [error]
Min <= Max
eld-5 [error]
if the element definition has a contentReference, it cannot have type, defaultValue, fixed, pattern, example, minValue, maxValue, maxLength, or binding
eld-6 [error]
Fixed value may only be specified if there is one type
eld-7 [error]
Pattern may only be specified if there is one type
eld-8 [error]
Pattern and fixed are mutually exclusive
eld-11 [error]
Binding can only be present for coded elements, string, and uri
eld-13 [error]
Types must be unique by code
eld-14 [error]
Constraints must be unique by key
eld-15 [error]
default value and meaningWhenMissing are mutually exclusive
eld-16 [error]
sliceName must be composed of proper tokens separated by "/"
eld-18 [error]
Must have a modifier reason if isModifier = true
eld-19 [error]
Element names cannot include some special characters
eld-20 [warning]
Element names should be simple alphanumerics with a max of 64 characters, or code generation tools may be broken
eld-22 [error]
sliceIsConstraining can only appear if slicename is present
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.path
Id
ElementDefinition.path
Type
Cardinality
1 - 1
Definition
The path identifies the element and is expressed as a "."-separated list of ancestor elements, beginning with the name of the resource or extension.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.representation
Id
ElementDefinition.representation
Type
Cardinality
0 - *
Definition
Codes that define how this element is represented in instances, when the deviation varies from the normal case.
Comment
In resources, this is rarely used except for special cases where the representation deviates from the normal, and can only be done in the base standard (and profiles must reproduce what the base standard does). This element is used quite commonly in Logical models when the logical models represent a specific serialization format (e.g. CDA, v2 etc.).
Binding
Strength
required
Description
How a property is represented when serialized.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.sliceName
Id
ElementDefinition.sliceName
Type
Cardinality
0 - 1
Definition
The name of this element definition slice, when slicing is working. The name must be a token with no dots or spaces. This is a unique name referring to a specific set of constraints applied to this element, used to provide a name to different slices of the same element.
Comment
The name SHALL be unique within the structure within the context of the constrained resource element. (Though to avoid confusion, uniqueness across all elements is recommended.).
Requirements
May also be used for code generation purposes.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
sliceIsConstraining
If this slice definition constrains an inherited slice definition (or not)
Path
ElementDefinition.sliceIsConstraining
Id
ElementDefinition.sliceIsConstraining
Type
Cardinality
0 - 1
Definition
If true, indicates that this slice definition is constraining a slice definition with the same name in an inherited profile. If false, the slice is not overriding any slice in an inherited profile. If missing, the slice might or might not be overriding a slice in an inherited profile, depending on the sliceName.
Comment
If set to true, an ancestor profile SHALL have a slicing definition with this name. If set to false, no ancestor profile is permitted to have a slicing definition with this name.
Requirements
Allows detection of a situation where an ancestor profile adds or removes slicing with the same name where that might impact the child profile.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.label
Id
ElementDefinition.label
Type
Cardinality
0 - 1
Definition
A single preferred label which is the text to display beside the element indicating its meaning or to use to prompt for the element in a user display or form.
Comment
See also the extension (http://hl7.org/fhir/StructureDefinition/elementdefinition-question)[extension-elementdefinition-question.html].
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.code
Id
ElementDefinition.code
Type
Cardinality
0 - *
Definition
A code that has the same meaning as the element in a particular terminology.
Comment
The concept SHALL be properly aligned with the data element definition and other constraints, as defined in the code system, including relationships, of any code listed here. Where multiple codes exist in a terminology that could correspond to the data element, the most granular code(s) should be selected, so long as they are not more restrictive than the data element itself. The mappings may be used to provide more or less granular or structured equivalences in the code system.
Requirements
Links the meaning of an element to an external terminology, and is very useful for searching and indexing.
Binding
Strength
example
Description
Codes that indicate the meaning of a data element.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.code.Coding.system
Id
Coding.system
Type
Cardinality
0 - 1
Definition
The identification of the code system that defines the meaning of the symbol in the code.
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 reference to some definition that establishes the system clearly and unambiguously.
Requirements
Need to be unambiguous about the source of the definition of the symbol.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.code.Coding.version
Id
Coding.version
Type
Cardinality
0 - 1
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.
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.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.code.Coding.code
Id
Coding.code
Type
Cardinality
0 - 1
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).
Comment
Requirements
Need to refer to a particular code in the system.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.code.Coding.display
Id
Coding.display
Type
Cardinality
0 - 1
Definition
A representation of the meaning of the code in the system, following the rules of the system.
Comment
Requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know the system.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.code.Coding.userSelected
Id
Coding.userSelected
Type
Cardinality
0 - 1
Definition
Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).
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.
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.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.slicing
Id
ElementDefinition.slicing
Type
Cardinality
0 - 1
Definition
Indicates that the element is sliced into a set of alternative definitions (i.e. in a structure definition, there are multiple different constraints on a single element in the base resource). Slicing can be used in any resource that has cardinality ..* on the base resource, or any resource with a choice of types. The set of slices is any elements that come after this in the element sequence that have the same path, until a shorter path occurs (the shorter path terminates the set).
Comment
The first element in the sequence, the one that carries the slicing, is the definition that applies to all the slices. This is based on the unconstrained element, but can apply any constraints as appropriate. This may include the common constraints on the children of the element.
Constraint
eld-1 [error]
If there are no discriminators, there must be a definition
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.slicing.discriminator
Id
ElementDefinition.slicing.discriminator
Type
Cardinality
0 - *
Definition
Designates which child elements are used to discriminate between the slices when processing an instance. If one or more discriminators are provided, the value of the child elements in the instance data SHALL completely distinguish which slice the element in the resource matches based on the allowed values for those elements in each of the slices.
Comment
If there is no discriminator, the content is hard to process, so this should be avoided.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.slicing.discriminator.type
Id
ElementDefinition.slicing.discriminator.type
Type
Cardinality
1 - 1
Definition
How the element value is interpreted when discrimination is evaluated.
Comment
Binding
Strength
required
Description
How an element value is interpreted when discrimination is evaluated.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.slicing.discriminator.path
Id
ElementDefinition.slicing.discriminator.path
Type
Cardinality
1 - 1
Definition
A FHIRPath expression, using [the simple subset of FHIRPath](fhirpath.html#simple), that is used to identify the element on which discrimination is based.
Comment
The only FHIRPath functions that are allowed are as(type), resolve(), and extension(url).
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.slicing.description
Id
ElementDefinition.slicing.description
Type
Cardinality
0 - 1
Definition
A human-readable text description of how the slicing works. If there is no discriminator, this is required to be present to provide whatever information is possible about how the slices can be differentiated.
Comment
If it's really not possible to differentiate them, the design should be re-evaluated to make the content usable.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
eld-1
Path
ElementDefinition.slicing.ordered
Id
ElementDefinition.slicing.ordered
Type
Cardinality
0 - 1
Definition
If the matching elements have to occur in the same order as defined in the profile.
Comment
Order should only be required when it is a pressing concern for presentation. Profile authors should consider making the order a feature of the rules about the narrative, not the rules about the data - requiring ordered data makes the profile much less re-usable.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.slicing.rules
Id
ElementDefinition.slicing.rules
Type
Cardinality
1 - 1
Definition
Whether additional slices are allowed or not. When the slices are ordered, profile authors can also say that additional slices are only allowed at the end.
Comment
Allowing additional elements makes for a much for flexible template - it's open for use in wider contexts, but also means that the content of the resource is not closed, and applications have to decide how to handle content not described by the profile.
Binding
Strength
required
Description
How slices are interpreted when evaluating an instance.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.short
Id
ElementDefinition.short
Type
Cardinality
0 - 1
Definition
A concise description of what this element means (e.g. for use in autogenerated summaries).
Comment
It is easy for a different short definition to change the meaning of an element and this can have nasty downstream consequences. Please be careful when providing short definitions in a profile.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.definition
Id
ElementDefinition.definition
Type
Cardinality
0 - 1
Definition
Provides a complete explanation of the meaning of the data element for human readability. For the case of elements derived from existing elements (e.g. constraints), the definition SHALL be consistent with the base definition, but convey the meaning of the element in the particular context of use of the resource. (Note: The text you are reading is specified in ElementDefinition.definition).
Comment
It is easy for a different definition to change the meaning of an element and this can have nasty downstream consequences. Please be careful when providing definitions in a profile.
Requirements
To allow a user to state the usage of an element in a particular context.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.comment
Id
ElementDefinition.comment
Type
Cardinality
0 - 1
Definition
Explanatory notes and implementation guidance about the data element, including notes about how to use the data properly, exceptions to proper use, etc. (Note: The text you are reading is specified in ElementDefinition.comment).
Comment
If it is possible to capture usage rules using constraints, that mechanism should be used in preference to this element.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.requirements
Id
ElementDefinition.requirements
Type
Cardinality
0 - 1
Definition
This element is for traceability of why the element was created and why the constraints exist as they do. This may be used to point to source materials or specifications that drove the structure of this element.
Comment
This element does not describe the usage of the element (that's done in comments), rather it's for traceability of *why* the element is either needed or why the constraints exist as they do. This may be used to point to source materials or specifications that drove the structure of this data element.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.alias
Id
ElementDefinition.alias
Type
Cardinality
0 - *
Definition
Identifies additional names by which this element might also be known.
Comment
Requirements
Allows for better easier recognition of the element by multiple communities, including international communities.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.min
Id
ElementDefinition.min
Type
Cardinality
0 - 1
Definition
The minimum number of times this element SHALL appear in the instance.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
eld-2
Path
ElementDefinition.max
Id
ElementDefinition.max
Type
Cardinality
0 - 1
Definition
The maximum number of times this element is permitted to appear in the instance.
Comment
Constraint
eld-3 [error]
Max SHALL be a number or "*"
ele-1 [error]
All FHIR elements must have a @value or children
Condition
eld-3
eld-2
Path
ElementDefinition.base
Id
ElementDefinition.base
Type
Cardinality
0 - 1
Definition
Information about the base definition of the element, provided to make it unnecessary for tools to trace the deviation of the element through the derived and related profiles. When the element definition is not the original definition of an element - i.g. either in a constraint on another type, or for elements from a super type in a snap shot - then the information in provided in the element definition may be different to the base definition. On the original definition of the element, it will be same.
Comment
The base information does not carry any information that could not be determined from the path and related profiles, but making this determination requires both that the related profiles are available, and that the algorithm to determine them be available. For tooling simplicity, the base information must always be populated in element definitions in snap shots, even if it is the same.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.base.path
Id
ElementDefinition.base.path
Type
Cardinality
1 - 1
Definition
The Path that identifies the base element - this matches the ElementDefinition.path for that element. Across FHIR, there is only one base definition of any element - that is, an element definition on a [StructureDefinition](structuredefinition.html#) without a StructureDefinition.base.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.base.min
Id
ElementDefinition.base.min
Type
Cardinality
1 - 1
Definition
Minimum cardinality of the base element identified by the path.
Comment
This is provided for consistency with max, and may affect code generation of mandatory elements of the base resource are generated differently (some reference implementations have done this).
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.base.max
Id
ElementDefinition.base.max
Type
Cardinality
1 - 1
Definition
Maximum cardinality of the base element identified by the path.
Comment
This is provided to code generation, since the serialization representation in JSON differs depending on whether the base element has max > 1. Also, some forms of code generation may differ.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.contentReference
Id
ElementDefinition.contentReference
Type
Cardinality
0 - 1
Definition
Identifies an element defined elsewhere in the definition whose content rules should be applied to the current element. ContentReferences bring across all the rules that are in the ElementDefinition for the element, including definitions, cardinality constraints, bindings, invariants etc.
Comment
ContentReferences can only be defined in specializations, not constrained types, and they cannot be changed and always reference the non-constrained definition.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
eld-5
Path
ElementDefinition.type
Id
ElementDefinition.type
Type
Cardinality
0 - *
Definition
The data type or resource that the value of this element is permitted to be.
Comment
The Type of the element can be left blank in a differential constraint, in which case the type is inherited from the resource. Abstract types are not permitted to appear as a type when multiple types are listed. (I.e. Abstract types cannot be part of a choice).
Constraint
eld-4 [error]
Aggregation may only be specified if one of the allowed types for the element is a reference
eld-17 [error]
targetProfile is only allowed if the type is Reference or canonical
ele-1 [error]
All FHIR elements must have a @value or children
Condition
eld-13
Path
ElementDefinition.type.code
Id
ElementDefinition.type.code
Type
Cardinality
1 - 1
Definition
URL of Data type or Resource that is a(or the) type used for this element. References are URLs that are relative to http://hl7.org/fhir/StructureDefinition e.g. "string" is a reference to http://hl7.org/fhir/StructureDefinition/string. Absolute URLs are only allowed in logical models.
Comment
If the element is a reference to another resource, this element contains "Reference", and the targetProfile element defines what resources can be referenced. The targetProfile may be a reference to the general definition of a resource (e.g. http://hl7.org/fhir/StructureDefinition/Patient).
Binding
Strength
extensible
Description
Either a resource or a data type, including logical model types.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.type.profile
Id
ElementDefinition.type.profile
Type
Cardinality
0 - *
Definition
Identifies a profile structure or implementation Guide that applies to the datatype this element refers to. If any profiles are specified, then the content must conform to at least one of them. The URL can be a local reference - to a contained StructureDefinition, or a reference to another StructureDefinition or Implementation Guide by a canonical URL. When an implementation guide is specified, the type SHALL conform to at least one profile defined in the implementation guide.
Comment
It is possible to profile backbone element (e.g. part of a resource), using the [profile-element](extension-elementdefinition-profile-element.html) extension.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
targetProfile
Profile (StructureDefinition or IG) on the Reference/canonical target - one must apply
Path
ElementDefinition.type.targetProfile
Id
ElementDefinition.type.targetProfile
Type
Cardinality
0 - *
Definition
Used when the type is "Reference" or "canonical", and identifies a profile structure or implementation Guide that applies to the target of the reference this element refers to. If any profiles are specified, then the content must conform to at least one of them. The URL can be a local reference - to a contained StructureDefinition, or a reference to another StructureDefinition or Implementation Guide by a canonical URL. When an implementation guide is specified, the target resource SHALL conform to at least one profile defined in the implementation guide.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.type.aggregation
Id
ElementDefinition.type.aggregation
Type
Cardinality
0 - *
Definition
If the type is a reference to another resource, how the resource is or can be aggregated - is it a contained resource, or a reference, and if the context is a bundle, is it included in the bundle.
Comment
See [Aggregation Rules](elementdefinition.html#aggregation) for further clarification.
Binding
Strength
required
Description
How resource references can be aggregated.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
eld-4
Path
ElementDefinition.type.versioning
Id
ElementDefinition.type.versioning
Type
Cardinality
0 - 1
Definition
Whether this reference needs to be version specific or version independent, or whether either can be used.
Comment
The base specification never makes a rule as to which form is allowed, but implementation guides may do this. See [Aggregation Rules](elementdefinition.html#aggregation) for further clarification.
Binding
Strength
required
Description
Whether a reference needs to be version specific or version independent, or whether either can be used.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.defaultValue[x]
Id
ElementDefinition.defaultValue[x]
Type
Cardinality
0 - 1
Definition
The value that should be used if there is no value stated in the instance (e.g. 'if not otherwise specified, the abstract is false').
Comment
Specifying a default value means that the property can never been unknown - it must always have a value. Further, the default value can never be changed, or changed in constraints on content models. Defining default values creates many difficulties in implementation (e.g. when is a value missing?). For these reasons, default values are (and should be) used extremely sparingly.
No default values are ever defined in the FHIR specification, nor can they be defined in constraints ("profiles") on data types or resources. This element only exists so that default values may be defined in logical models.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
eld-15
Path
ElementDefinition.meaningWhenMissing
Id
ElementDefinition.meaningWhenMissing
Type
Cardinality
0 - 1
Definition
The Implicit meaning that is to be understood when this element is missing (e.g. 'when this element is missing, the period is ongoing').
Comment
Implicit meanings for missing values can only be specified on a resource, data type, or extension definition, and never in a profile that applies to one of these. An implicit meaning for a missing value can never be changed, and specifying one has the consequence that constraining its use in profiles eliminates use cases as possibilities, not merely moving them out of scope.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
eld-15
Path
ElementDefinition.orderMeaning
Id
ElementDefinition.orderMeaning
Type
Cardinality
0 - 1
Definition
If present, indicates that the order of the repeating element has meaning and describes what that meaning is. If absent, it means that the order of the element has no meaning.
Comment
This element can only be asserted on repeating elements and can only be introduced when defining resources or data types. It can be further refined profiled elements but if absent in the base type, a profile cannot assert meaning.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.fixed[x]
Id
ElementDefinition.fixed[x]
Type
Cardinality
0 - 1
Definition
Specifies a value that SHALL be exactly the value for this element in the instance. For purposes of comparison, non-significant whitespace is ignored, and all values must be an exact match (case and accent sensitive). Missing elements/attributes must also be missing.
Comment
This is not recommended for Coding and CodeableConcept since these often have highly contextual properties such as version or display.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
eld-5
eld-6
eld-8
Path
ElementDefinition.pattern[x]
Id
ElementDefinition.pattern[x]
Type
Cardinality
0 - 1
Definition
Specifies a value that the value in the instance SHALL follow - that is, any value in the pattern must be found in the instance. Other additional values may be found too. This is effectively constraint by example.
When pattern[x] is used to constrain a primitive, it means that the value provided in the pattern[x] must match the instance value exactly.
When pattern[x] is used to constrain an array, it means that each element provided in the pattern[x] array must (recursively) match at least one element from the instance array.
When pattern[x] is used to constrain a complex object, it means that each property in the pattern must be present in the complex object, and its value must recursively match -- i.e.,
1. If primitive: it must match exactly the pattern value
2. If a complex object: it must match (recursively) the pattern value
3. If an array: it must match (recursively) the pattern value.
Comment
Mostly used for fixing values of CodeableConcept. In general, pattern[x] is not intended for use with primitive types, where is has the same meaning as fixed[x].
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
eld-5
eld-7
eld-8
Path
ElementDefinition.example
Id
ElementDefinition.example
Type
Cardinality
0 - *
Definition
A sample value for this element demonstrating the type of information that would typically be found in the element.
Comment
Examples will most commonly be present for data where it's not implicitly obvious from either the data type or value set what the values might be. (I.e. Example values for dates or quantities would generally be unnecessary.) If the example value is fully populated, the publication tool can generate an instance automatically.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.example.label
Id
ElementDefinition.example.label
Type
Cardinality
1 - 1
Definition
Describes the purpose of this example amoung the set of examples.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.example.value[x]
Id
ElementDefinition.example.value[x]
Type
Cardinality
1 - 1
Definition
The actual value for the element, which must be one of the types allowed for this element.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.minValue[x]
Id
ElementDefinition.minValue[x]
Type
Cardinality
0 - 1
Definition
The minimum allowed value for the element. The value is inclusive. This is allowed for the types date, dateTime, instant, time, decimal, integer, and Quantity.
Comment
Except for date/date/instant, the type of the minValue[x] SHALL be the same as the specified type of the element. For the date/dateTime/instant values, the type of minValue[x] SHALL be either the same, or a [Duration](datatypes.html#Duration) which specifies a relative time limit to the current time. The duration value is positive, and is subtracted from the current clock to determine the minimum allowable value. A minimum value for a Quantity is interpreted as an canonical minimum - e.g. you cannot provide 100mg if the minimum value is 10g.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.maxValue[x]
Id
ElementDefinition.maxValue[x]
Type
Cardinality
0 - 1
Definition
The maximum allowed value for the element. The value is inclusive. This is allowed for the types date, dateTime, instant, time, decimal, integer, and Quantity.
Comment
Except for date/date/instant, the type of the maxValue[x] SHALL be the same as the specified type of the element. For the date/dateTime/instant values, the type of maxValue[x] SHALL be either the same, or a [Duration](datatypes.html#Duration) which specifies a relative time limit to the current time. The duration value is positive, and is added to the current clock to determine the maximum allowable value. A maximum value for a Quantity is interpreted as an canonical maximum - e.g. you cannot provide 10g if the maximum value is 50mg.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.maxLength
Id
ElementDefinition.maxLength
Type
Cardinality
0 - 1
Definition
Indicates the maximum length in characters that is permitted to be present in conformant instances and which is expected to be supported by conformant consumers that support the element.
Comment
Receivers are not required to reject instances that exceed the maximum length. The full length could be stored. In some cases, data might be truncated, though truncation should be undertaken with care and an understanding of the consequences of doing so. If not specified, there is no conformance expectation for length support.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.condition
Id
ElementDefinition.condition
Type
Cardinality
0 - *
Definition
A reference to an invariant that may make additional statements about the cardinality or value in the instance.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.constraint
Id
ElementDefinition.constraint
Type
Cardinality
0 - *
Definition
Formal constraints such as co-occurrence and other constraints that can be computationally evaluated within the context of the instance.
Comment
Constraints should be declared on the "context" element - the lowest element in the hierarchy that is common to all nodes referenced by the constraint.
Constraint
eld-21 [warning]
Constraints should have an expression or else validators will not be able to enforce them
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.constraint.key
Id
ElementDefinition.constraint.key
Type
Cardinality
1 - 1
Definition
Allows identification of which elements have their cardinalities impacted by the constraint. Will not be referenced for constraints that do not affect cardinality.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
eld-14
Path
ElementDefinition.constraint.requirements
Id
ElementDefinition.constraint.requirements
Type
Cardinality
0 - 1
Definition
Description of why this constraint is necessary or appropriate.
Comment
To be used if the reason for the constraint might not be intuitive to all implementers.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.constraint.severity
Id
ElementDefinition.constraint.severity
Type
Cardinality
1 - 1
Definition
Identifies the impact constraint violation has on the conformance of the instance.
Comment
This allows constraints to be asserted as "shall" (error) and "should" (warning).
Binding
Strength
required
Description
SHALL applications comply with this constraint?
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.constraint.human
Id
ElementDefinition.constraint.human
Type
Cardinality
1 - 1
Definition
Text that can be used to describe the constraint in messages identifying that the constraint has been violated.
Comment
Should be expressed in business terms as much as possible.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.constraint.expression
Id
ElementDefinition.constraint.expression
Type
Cardinality
0 - 1
Definition
A [FHIRPath](fhirpath.html) expression of constraint that can be executed to see if this constraint is met.
Comment
In the absense of an expression, the expression is likely not enforceable by validators, and might be missed by many systems.
Requirements
Used by validation tooling tests of the validity of the resource.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.constraint.xpath
Id
ElementDefinition.constraint.xpath
Type
Cardinality
0 - 1
Definition
An XPath expression of constraint that can be executed to see if this constraint is met.
Comment
Elements SHALL use "f" as the namespace prefix for the FHIR namespace, and "x" for the xhtml namespace, and SHALL NOT use any other prefixes. Note: XPath is generally considered not useful because it does not apply to JSON and other formats and because of XSLT implementation issues, and may be removed in the future.
Requirements
Used in Schematron tests of the validity of the resource.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.constraint.source
Id
ElementDefinition.constraint.source
Type
Cardinality
0 - 1
Definition
A reference to the original source of the constraint, for traceability purposes.
Comment
This is used when, e.g. rendering, where it is not useful to present inherited constraints when rendering the snapshot.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.mustSupport
Id
ElementDefinition.mustSupport
Type
Cardinality
0 - 1
Definition
If true, implementations that produce or consume resources SHALL provide "support" for the element in some meaningful way. If false, the element may be ignored and not supported. If false, whether to populate or use the data element in any way is at the discretion of the implementation.
Comment
"Something useful" is context dependent and impossible to describe in the base FHIR specification. For this reason, tue mustSupport flag is never set to true by the FHIR specification itself - it is only set to true in profiles. A profile on a type can always make musSupport = true if it is false in the base type but cannot make mustSupport = false if it is true in the base type. This is done in [Resource Profiles](profiling.html#mustsupport), where the profile labels an element as mustSupport=true. When a profile does this, it SHALL also make clear exactly what kind of "support" is required, as this can mean many things. Note that an element that has the property IsModifier is not necessarily a "key" element (e.g. one of the important elements to make use of the resource), nor is it automatically mustSupport - however both of these things are more likely to be true for IsModifier elements than for other elements.
Requirements
Allows a profile to set expectations for system capabilities beyond merely respecting cardinality constraints.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.isModifier
Id
ElementDefinition.isModifier
Type
Cardinality
0 - 1
Definition
If true, the value of this element affects the interpretation of the element or resource that contains it, and the value of the element cannot be ignored. Typically, this is used for status, negation and qualification codes. The effect of this is that the element cannot be ignored by systems: they SHALL either recognize the element and process it, and/or a pre-determination has been made that it is not relevant to their particular system.
Comment
Only the definition of an element can set IsModifier true - either the specification itself or where an extension is originally defined. Once set, it cannot be changed in derived profiles. An element/extension that has isModifier=true SHOULD also have a minimum cardinality of 1, so that there is no lack of clarity about what to do if it is missing. If it can be missing, the definition SHALL make the meaning of a missing element clear.
Requirements
Allows elements to be introduced into a specification that can't safely be ignored by applications that don't recognize them.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.isModifierReason
Id
ElementDefinition.isModifierReason
Type
Cardinality
0 - 1
Definition
Explains how that element affects the interpretation of the resource or element that contains it.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.isSummary
Id
ElementDefinition.isSummary
Type
Cardinality
0 - 1
Definition
Whether the element should be included if a client requests a search with the parameter _summary=true.
Comment
Some resources include a set of simple metadata, and some very large data. This element is used to reduce the quantity of data returned in searches. Note that servers may pre-cache summarized resources for optimal performance, so servers might not support per-profile use of the isSummary flag. When a request is made with _summary=true, serailisers only include elements marked as 'isSummary = true'. Other than Attachment.data, all data type properties are included in the summary form. In resource and data type definitions, if an element is at the root or has a parent that is 'mustSupport' and the minimum cardinality is 1 or the element is a modifier, it must be marked as isSummary=true.
Requirements
Allow clients to search through large resources quickly.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.binding
Id
ElementDefinition.binding
Type
Cardinality
0 - 1
Definition
Binds to a value set if this element is coded (code, Coding, CodeableConcept, Quantity), or the data types (string, uri).
Comment
For a CodeableConcept, when no codes are allowed - only text, use a binding of strength "required" with a description explaining that no coded values are allowed and what sort of information to put in the "text" element.
Constraint
eld-12 [error]
ValueSet SHALL start with http:// or https:// or urn:
ele-1 [error]
All FHIR elements must have a @value or children
Condition
eld-11
Path
ElementDefinition.binding.strength
Id
ElementDefinition.binding.strength
Type
Cardinality
1 - 1
Definition
Indicates the degree of conformance expectations associated with this binding - that is, the degree to which the provided value set must be adhered to in the instances.
Comment
For further discussion, see [Using Terminologies](terminologies.html).
Binding
Strength
required
Description
Indication of the degree of conformance expectations associated with a binding.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.binding.description
Id
ElementDefinition.binding.description
Type
Cardinality
0 - 1
Definition
Describes the intended use of this particular set of codes.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.binding.valueSet
Id
ElementDefinition.binding.valueSet
Type
Cardinality
0 - 1
Definition
Refers to the value set that identifies the set of codes the binding refers to.
Comment
The reference may be version-specific or not (e.g. have a |[version] at the end of the canonical URL).
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
eld-12
Path
ElementDefinition.mapping
Id
ElementDefinition.mapping
Type
Cardinality
0 - *
Definition
Identifies a concept from an external specification that roughly corresponds to this element.
Comment
Mappings are not necessarily specific enough for safe translation.
Requirements
Provides guidance to implementers familiar with or converting content from other specifications.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.mapping.identity
Id
ElementDefinition.mapping.identity
Type
Cardinality
1 - 1
Definition
An internal reference to the definition of a mapping.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.mapping.map
Id
ElementDefinition.mapping.map
Type
Cardinality
1 - 1
Definition
Expresses what part of the target specification corresponds to this element.
Comment
For most mappings, the syntax is undefined. Syntax will be provided for mappings to the RIM. Multiple mappings may be possible and may include constraints on other resource elements that identify when a particular mapping applies.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
ElementDefinition.mapping.comment
Id
ElementDefinition.mapping.comment
Type
Cardinality
0 - 1
Definition
Comments that provide information about the mapping or its use.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children