BEGIN
DBMS_XMLSCHEMA.REGISTERSCHEMA (
  schemaurl => 'http://apex.oracle.com/public/bookCover.xsd'
, schemadoc => 
'
 <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <xsd:element name="cover" type="coverType"/>
    <xsd:complexType name="coverType">
      <xsd:sequence>
        <xsd:element name="title" type="xsd:string"/>
        <xsd:element name="author" type="xsd:string"
                     maxOccurs="unbounded"/>
        <xsd:element name="publisher" type="xsd:string"/>
        <xsd:element name="pubdate" type="xsd:string"/>
        <xsd:element name="isbn" type="xsd:string"/>
        <xsd:element name="pages" type="xsd:string"/>
      </xsd:sequence>
    </xsd:complexType>
</xsd:schema>
'
);
END;
/