<StructureDefinition xmlns="http://hl7.org/fhir">
  <url value="https://example.org/fhir/StructureDefinition/MyModel" />
  <name value="MyModel" />
  <status value="draft" />
  <fhirVersion value="5.0.0" />
  <kind value="logical" />
  <abstract value="false" />
  <type value="https://example.org/fhir/StructureDefinition/MyModel" />
  <baseDefinition value="http://hl7.org/fhir/StructureDefinition/Element" />
  <derivation value="specialization" />
  <snapshot>
    <element id="MyModel">
      <path value="MyModel" />
      <short value="Base for all elements" />
      <definition value="Base definition for all elements in a resource." />
      <min value="0" />
      <max value="*" />
      <base>
        <path value="MyModel" />
        <min value="0" />
        <max value="*" />
      </base>
      <type>
        <code value="Element" />
      </type>
      <condition value="ele-1" />
      <constraint>
        <key value="ele-1" />
        <severity value="error" />
        <human value="All FHIR elements must have a @value or children" />
        <expression value="hasValue() or (children().count() &gt; id.count())" />
        <source value="http://hl7.org/fhir/StructureDefinition/Element" />
      </constraint>
      <mapping>
        <identity value="rim" />
        <map value="n/a" />
      </mapping>
    </element>
    <element id="MyModel.id">
      <path value="MyModel.id" />
      <representation value="xmlAttr" />
      <short value="Unique id for inter-element referencing" />
      <definition value="Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces." />
      <min value="0" />
      <max value="1" />
      <base>
        <path value="Element.id" />
        <min value="0" />
        <max value="1" />
      </base>
      <type>
        <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type">
          <valueUrl value="string" />
        </extension>
        <code value="http://hl7.org/fhirpath/System.String" />
      </type>
      <mapping>
        <identity value="rim" />
        <map value="n/a" />
      </mapping>
    </element>
    <element id="MyModel.extension">
      <path value="MyModel.extension" />
      <slicing>
        <discriminator>
          <type value="value" />
          <path value="url" />
        </discriminator>
        <description value="Extensions are always sliced by (at least) url" />
        <rules value="open" />
      </slicing>
      <short value="Additional content defined by implementations" />
      <definition value="May be used to represent additional information that is not part of the basic definition of the element. 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 can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension." />
      <comment value="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." />
      <alias value="extensions" />
      <alias value="user content" />
      <min value="0" />
      <max value="*" />
      <base>
        <path value="Element.extension" />
        <min value="0" />
        <max value="*" />
      </base>
      <type>
        <code value="Extension" />
      </type>
      <condition value="ele-1" />
      <constraint>
        <key value="ele-1" />
        <severity value="error" />
        <human value="All FHIR elements must have a @value or children" />
        <expression value="hasValue() or (children().count() &gt; id.count())" />
        <source value="http://hl7.org/fhir/StructureDefinition/Element" />
      </constraint>
      <constraint>
        <key value="ext-1" />
        <severity value="error" />
        <human value="Must have either extensions or value[x], not both" />
        <expression value="extension.exists() != value.exists()" />
        <source value="http://hl7.org/fhir/StructureDefinition/Extension" />
      </constraint>
      <mapping>
        <identity value="rim" />
        <map value="n/a" />
      </mapping>
      <mapping>
        <identity value="rim" />
        <map value="N/A" />
      </mapping>
    </element>
    <element id="MyModel.email">
      <path value="MyModel.email" />
      <short value="Primitive Type string" />
      <definition value="A sequence of Unicode characters" />
      <comment value="Note that FHIR strings SHALL NOT exceed 1MB in size" />
      <min value="0" />
      <max value="*" />
      <base>
        <path value="MyModel.email" />
        <min value="0" />
        <max value="*" />
      </base>
      <type>
        <code value="string" />
        <profile value="http://hl7.org/fhir/StructureDefinition/string" />
      </type>
      <condition value="ele-1" />
      <constraint>
        <key value="ele-1" />
        <severity value="error" />
        <human value="All FHIR elements must have a @value or children" />
        <expression value="hasValue() or (children().count() &gt; id.count())" />
        <source value="http://hl7.org/fhir/StructureDefinition/Element" />
      </constraint>
      <constraint>
        <key value="email-format" />
        <severity value="error" />
        <human value="email format" />
        <expression value="^\S+@\S+\.\S+$" />
        <source value="https://example.org/fhir/StructureDefinition/MyModel" />
      </constraint>
      <mapping>
        <identity value="rim" />
        <map value="n/a" />
      </mapping>
    </element>
  </snapshot>
  <differential>
    <element id="MyModel">
      <path value="MyModel" />
      <min value="0" />
      <max value="*" />
      <type>
        <code value="Element" />
      </type>
    </element>
    <element id="MyModel.email">
      <path value="MyModel.email" />
      <min value="0" />
      <max value="*" />
      <type>
        <code value="string" />
        <profile value="http://hl7.org/fhir/StructureDefinition/string" />
      </type>
      <constraint>
        <key value="email-format" />
        <severity value="error" />
        <human value="email format" />
        <expression value="^\S+@\S+\.\S+$" />
      </constraint>
    </element>
  </differential>
</StructureDefinition>