XML/XML Schema/xlink

attribute with referencing xlink

File: Data.xml
<?xml version="1.0"?>
<Mission xmlns="http://www.wbex.ru/unit/mission"
         xmlns:xlink="http://www.w3.org/1999/xlink/namespace"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation=
                   "http://www.wbex.ru/unit/mission
                    Schema.xsd">
    <MISSION-DATA>...</MISSION-DATA>
    <Sortie xlink:href="https://www.wbex.ru/"/>
</Mission>
File: Schema.xsd
<?xml version="1.0"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            targetNamespace="http://www.wbex.ru/unit/mission"
            xmlns="http://www.wbex.ru/unit/mission"
            xmlns:xlink="http://www.w3.org/1999/xlink/namespace"
            elementFormDefault="qualified">
    <xsd:import namespace="http://www.w3.org/1999/xlink/namespace"
                schemaLocation="xlink.xsd"/>
    <xsd:element name="Mission">
        <xsd:complexType>
             <xsd:sequence>
                 <xsd:element name="MISSION-DATA" type="xsd:string"/>
                 <xsd:element name="Sortie" maxOccurs="unbounded"> 
                     <xsd:complexType>
                         <xsd:sequence/>
                         <xsd:attribute ref="xlink:href" use="required"/>
                     </xsd:complexType>
                 </xsd:element>
            </xsd:sequence>
        </xsd:complexType>
    </xsd:element>
</xsd:schema>
File: xlink.xsd
<?xml version="1.0"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            targetNamespace="http://www.w3.org/1999/xlink/namespace"
            xmlns="http://www.w3.org/1999/xlink/namespace"
            elementFormDefault="qualified">
    <xsd:attribute name="href" type="xsd:anyURI"/>
</xsd:schema>

Use xlink to import another XML schema

File: Data.xml
<?xml version="1.0"?>
<Sortie xmlns="http://www.wbex.ru"
         xmlns:xlink="http://www.w3.org/1999/xlink/namespace"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation=
                   "http://www.wbex.ru
                    Schema.xsd">
    <SORTIE-DATA>...</SORTIE-DATA>
    <Aircraft xlink:href="https://www.wbex.ru"/>
</Sortie>

File: Schema.xsd
<?xml version="1.0"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            targetNamespace="http://www.wbex.ru"
            xmlns="http://www.wbex.ru"
            xmlns:xlink="http://www.w3.org/1999/xlink/namespace"
            elementFormDefault="qualified">
    <xsd:import namespace="http://www.w3.org/1999/xlink/namespace"
                schemaLocation="xlink.xsd"/>
    <xsd:element name="Sortie">
        <xsd:complexType>
             <xsd:sequence>
                 <xsd:element name="SORTIE-DATA" type="xsd:string"/>
                 <xsd:element name="Aircraft" maxOccurs="unbounded"> 
                     <xsd:complexType>
                         <xsd:sequence/>
                         <xsd:attribute ref="xlink:href" use="required"/>
                     </xsd:complexType>
                 </xsd:element>
            </xsd:sequence>
        </xsd:complexType>
    </xsd:element>
</xsd:schema>

File: xlink.xsd
<?xml version="1.0"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            targetNamespace="http://www.w3.org/1999/xlink/namespace"
            xmlns="http://www.w3.org/1999/xlink/namespace"
            elementFormDefault="qualified">
    <xsd:attribute name="href" type="xsd:anyURI"/>
</xsd:schema>