1 <?xml version="1.0" encoding="UTF-8"?>

     2 <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"

     3            xmlns:example="http://www.example.org/root"

     4            xmlns="http://www.example.org/root"

     5            targetNamespace="http://www.example.org/root"

     6            elementFormDefault="qualified" attributeFormDefault="unqualified">

     7     <xs:element name="Root">

     8         <xs:complexType>

     9             <xs:choice maxOccurs="unbounded">

    10                 <xs:element ref="Object" />

    11             </xs:choice>

    12         </xs:complexType>

    13         <xs:key name="name_key">

    14             <xs:selector xpath=".//example:Object" />

    15             <xs:field xpath="@name" />

    16         </xs:key>

    17         <xs:keyref name="Collectiontype_defined" refer="name_key">

    18             <xs:selector xpath=".//example:CollectionMember" />

    19             <xs:field xpath="@type" />

    20         </xs:keyref>

    21     </xs:element>

    22     <xs:element name="Members">

    23         <xs:complexType>

    24             <xs:group ref="example:memberTypes" minOccurs="0"

    25                       maxOccurs="unbounded" />

    26         </xs:complexType>

    27     </xs:element>

    28     <xs:element name="Object">

    29         <xs:complexType>

    30             <xs:sequence>

    31                 <xs:element ref="Members" minOccurs="0" />

    32             </xs:sequence>

    33             <xs:attributeGroup ref="example:typedMemberAttributes" />

    34             <xs:attributeGroup ref="example:namedMemberAttributes" />

    35         </xs:complexType>

    36         <xs:unique name="ObjectElementNameUniqueness">

    37             <xs:selector xpath="example:Members/*" />

    38             <xs:field xpath="@name" />

    39         </xs:unique>

    40     </xs:element>

    41     <xs:element name="Collection">

    42         <xs:complexType>

    43             <xs:sequence>

    44                 <xs:element ref="CollectionMembers" />

    45             </xs:sequence>

    46             <xs:attributeGroup ref="example:namedMemberAttributes" />

    47         </xs:complexType>

    48     </xs:element>

    49     <xs:element name="CollectionMembers">

    50         <xs:complexType>

    51             <xs:sequence>

    52                 <xs:element ref="CollectionMember" minOccurs="2"

    53                             maxOccurs="unbounded" />

    54             </xs:sequence>

    55         </xs:complexType>

    56     </xs:element>

    57     <xs:element name="CollectionMember">

    58         <xs:complexType>

    59             <xs:sequence>

    60                 <xs:element ref="Members" minOccurs="0"

    61                             maxOccurs="unbounded" />

    62             </xs:sequence>

    63             <xs:attributeGroup ref="example:typedMemberAttributes" />

    64             <xs:attributeGroup ref="example:namedMemberAttributes" />

    65         </xs:complexType>

    66     </xs:element>

    67     <xs:element name="String">

    68         <xs:complexType>

    69             <xs:attributeGroup ref="example:namedMemberAttributes" />

    70         </xs:complexType>

    71     </xs:element>

    72     <xs:group name="memberTypes">

    73         <xs:choice>

    74             <xs:element ref="String" />

    75             <xs:element ref="Collection" />

    76         </xs:choice>

    77     </xs:group>

    78     <xs:attributeGroup name="namedMemberAttributes">

    79         <xs:attribute name="name" type="xs:Name" use="required" />

    80     </xs:attributeGroup>

    81     <xs:attributeGroup name="typedMemberAttributes">

    82         <xs:attribute name="type" type="xs:Name" />

    83     </xs:attributeGroup>

    84 </xs:schema>