<ids>
  <baseId default="" id="" prefix="" type="">{0,unbounded}</baseId>
  <defaultBaseId id="" type="">{0,unbounded}</defaultBaseId>
  <id assigningAuthority="" extension="" root="">{0,unbounded}</id>
  <identifierAssociation conceptFlexibility="" conceptId="" effectiveDate="" expirationDate="" lastModifiedDate="" officialReleaseDate="" ref="" refdisplay="" versionLabel="">{0,unbounded}</identifierAssociation>
</ids>

<xs:element name="ids">
  <xs:complexType>
    <xs:sequence>
      <xs:element ref="baseId" minOccurs="0" maxOccurs="unbounded"/>
      <xs:element ref="defaultBaseId" minOccurs="0" maxOccurs="unbounded"/>
      <xs:element ref="id" minOccurs="0" maxOccurs="unbounded"/>
      <xs:element ref="identifierAssociation" minOccurs="0" maxOccurs="unbounded"/>
    </xs:sequence>
  </xs:complexType>
  <xs:key name="unique-id-root">
    <xs:selector xpath="id"/>
    <xs:field xpath="@root"/>
  </xs:key>
  <xs:key name="unique-baseId">
    <xs:selector xpath="baseId"/>
    <xs:field xpath="@id"/>
  </xs:key>
  <xs:key name="unique-defaultBaseId">
    <xs:selector xpath="defaultBaseId"/>
    <xs:field xpath="@id"/>
  </xs:key>
</xs:element>