src-resolve: Cannot resolve the name 'PkReportsTo' to a(n) 'identity constraint' component. [XSD]

Question

I was trying to create FK and PK in the XML schema, but it is showing an error in the featured code above. Is shows the message: src-resolve: Cannot resolve the name 'PkReportsTo' to a(n) 'identity constraint' component. [XSD]

<xs:schema 
xmlns:xs="http://www.w3.org/2001/XMLSchema" 
xmlns="http://www.ricardoterra.com.br" 
elementFormDefault="qualified">
    <xs:element name="employees">
        <xs:complexType>
            <xs:sequence>
                <xs:element name="employee" maxOccurs="unbounded"> 
                    <xs:complexType>
                        <xs:all>
                            <xs:element name="firstName" type="xs:string"></xs:element>
                            <xs:element name="lastName" type="xs:string"></xs:element>
                            <xs:element name="extension">
                                <xs:simpleType>
                                    <xs:restriction base="xs:string"> 
                                        <xs:pattern value="([x][1-9])\w+"></xs:pattern>
                                    </xs:restriction>
                                </xs:simpleType>
                            </xs:element>
                            <xs:element name="email">
                                <xs:simpleType>
                                    <xs:restriction base="xs:string"> 
                                        <xs:pattern value="([a-z])\w+(@)([a-z])\w+(.[a-z]+)*"></xs:pattern>
                                    </xs:restriction>
                                </xs:simpleType>
                            </xs:element>
                            <xs:element name="officeCode" type="xs:string"></xs:element>
                            <xs:element name="jobTitle" type="xs:string"></xs:element>
                            <xs:element name="reportsTo" type="xs:integer" minOccurs="0">
                              
                            </xs:element>
                        </xs:all>
                        <xs:attribute name="number" type="xs:integer"></xs:attribute>
                    </xs:complexType>
                </xs:element>
            </xs:sequence>
        </xs:complexType>
        <xs:unique name="number"> 
            <xs:selector xpath="employee"></xs:selector>
            <xs:field xpath="@number"></xs:field>
        </xs:unique>
        <xs:key name="PkEmploye">
            <xs:selector xpath="employee"/>
            <xs:field xpath="@number"></xs:field>
        </xs:key>
        <xs:key name="PkReportsTo">
            <xs:selector xpath="employee/reportsTo"></xs:selector>
            <xs:field xpath="."></xs:field>
        </xs:key>
        <xs:keyref name="FKtoReportsToEmployee" refer="PkReportsTo">
            <xs:selector xpath="employee"></xs:selector>
            <xs:field xpath="@number"></xs:field>
        </xs:keyref>
    </xs:element>
</xs:schema>

I am with a error at the part of my code:

<xs:keyref name="FKtoReportsToEmployee" refer="PkReportsTo">
     <xs:selector xpath="employee"></xs:selector>
     <xs:field xpath="@number"></xs:field>
</xs:keyref>

I don't know why.

Answer 1

I think you want the target namespace of the schema to be http://www.ricardoterra.com.br so use

<xs:schema 
    xmlns:xs="http://www.w3.org/2001/XMLSchema" 
    xmlns="http://www.ricardoterra.com.br" 
    targetNamespace="http://www.ricardoterra.com.br"
    elementFormDefault="qualified">

and that error is likely to go away.