<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">


  <xs:element name="choose1">
    <xs:complexType>
      <xs:choice >
        <xs:element name="item"  type="xs:string"/>
        <xs:element name="param" type="xs:integer"/>
      </xs:choice>
    </xs:complexType>
  </xs:element>

  <xs:complexType name="choose2">

    <xs:sequence>
      <xs:element name="item"  type="xs:string"/>


      <xs:choice>
        <xs:element name="b"  type="xs:string"/>
        <xs:element name="c"  type="xs:string"/>
      </xs:choice>

    </xs:sequence>
    <xs:attribute name="a1" use="required" type="xs:dateTime"/>
    <xs:attribute name="a2" use="required" type="xs:dateTime"/>
    <xs:attribute name="a0"  type="xs:dateTime"/>
  </xs:complexType>
</xs:schema>