XSD 1.1 - "xs:alternative" does not match with the xml file

Question

My xml does not match because of xs:alternative from xsd.

XML code

<?xml version="1.0" encoding="UTF-8"?>
<install xmlns="h4a:install" xmlns:h4a="https://www.hive-4-apps.org/xml-shemas/install.xsd" >
    <database>
        <tables>
           <table name="foo">
               <column name="foo_id"    type="bigint(20)" />
                <column name="foo_name"     type="varchar(255)" />
                <column name="foo_type"     type="varchar(35)" />
                <column name="foo_type_id"  type="int(40)"/>
                <key type="unique">
                    <column ref="foo_name"/>
                    <column ref="foo_type"/>
                </key>
                <key type="index" name="foo_type_id" col_name="form_type_id" />
            </table>
        </tables>
    </database>
</install>

XSD code

<?xml version="1.0" encoding="UTF-8" ?>
<xs:schema elementFormDefault="qualified" targetNamespace="h4a:install" xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <xs:element name="install" type="h4a:installType" xmlns:h4a="h4a:install"/>
    <xs:complexType name="installType">
        <xs:sequence>
            <xs:element type="databaseType" name="database"/>
        </xs:sequence>
    </xs:complexType>
    <xs:complexType name="columnType">
        <xs:simpleContent>
            <xs:extension base="xs:string">
                 <xs:attribute type="xs:string"  name="name"     use="required"/>
                 <xs:attribute type="xs:string"  name="type"     use="required"/>
            </xs:extension>
        </xs:simpleContent>
    </xs:complexType>
    <xs:complexType name="columnKeyType">
        <xs:simpleContent>
            <xs:extension base="xs:string">
                <xs:attribute type="xs:string"  name="ref" use="required"/> 
            </xs:extension>
        </xs:simpleContent>
    </xs:complexType>
    <xs:complexType name="tableType">
        <xs:sequence>
            <xs:element type="columnType" name="column" maxOccurs="unbounded" minOccurs="0"/>
            <xs:element type="keyType" name="key" maxOccurs="unbounded" minOccurs="0">
                <xs:alternative type="keyIndexType" test="@type='index'"/>
                <xs:alternative test="@type='unique'" type="KeyUniqueType"/>
            </xs:element>
        </xs:sequence>
        <xs:attribute type="xs:string" name="name" use="required"/>
    </xs:complexType>
    <xs:complexType name="tablesType">
        <xs:sequence>
            <xs:element type="tableType" name="table" maxOccurs="unbounded"/>
        </xs:sequence>
    </xs:complexType>
    <xs:complexType name="databaseType">
        <xs:sequence>
            <xs:element type="tablesType" name="tables" minOccurs="0"/>
        </xs:sequence>
    </xs:complexType>
    <xs:complexType name="keyType">
         <xs:attribute name="type" use="required">
             <xs:simpleType>
                 <xs:restriction base="xs:string">
                     <xs:pattern value="index|unique"/>
                 </xs:restriction>
             </xs:simpleType>
        </xs:attribute>   
    </xs:complexType>
    <xs:complexType name="keyIndexType">
        <xs:simpleContent>
            <xs:extension base="keyType">
                <xs:attribute type="xs:string" name="name" use="required"/>
                <xs:attribute type="xs:string" name="col_name" use="required"/>
            </xs:extension>
        </xs:simpleContent>
    </xs:complexType>
   <xs:complexType name="KeyUniqueType">
       <xs:complexContent>
            <xs:extension base="keyType">
                <xs:sequence>
                    <xs:element type="columnKeyType" name="column" maxOccurs="unbounded"/>  
                </xs:sequence>
            </xs:extension>
       </xs:complexContent>
    </xs:complexType>
</xs:schema>

I tried several possibilities without success. What is wrong in my xsd ?

Answer 1

It seems to be a problem of XSD 1.1 processor (again). Actually, PHPStorm support so a part of XML Shema 1.1.

See here

According to PHPStorm, there are no error in my xsd, but it does not validate correctly XML files with xs:alternative.

All XML Shema 1.1 validator are paid ( oxygen, Altova ) except a java tool not really useful for my case : xerces

XML tool of Notepad++ support only XSD 1.0.

Conclusion : either find a workaround with xsd 1.0, or accept to get errors until PHPStorm support correctly it.