What is an XML schema for representing a dictionary?

Question

Suppose I have an instance of Dictionary<string, string> , like this:

{{"a", "1"}, {"b", "2"}}

There are several ways to represent it in XML:

 <root> <item> <key>a</key> <value>1</value> </item> <item> <key>b</key> <value>2</value> </item> </root> 

OR

 <root> <item key="a" value="1"/> <item key="b" value="2"/> </root> 

OR

 <root> <a>1</a> <b>2</b> </root> 

What is an XML schema for describing each view?

Thanks.

Answer 1

Take a look at xs:unique . For 1st XML, the appropriate XSD is:

 <?xml version="1.0" encoding="utf-8"?> <xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:element name="root"> <xs:complexType> <xs:sequence> <xs:element maxOccurs="unbounded" name="item"> <xs:complexType> <xs:sequence> <xs:element name="key" type="xs:string" /> <xs:element name="value" type="xs:string" /> </xs:sequence> </xs:complexType> </xs:element> </xs:sequence> </xs:complexType> <xs:unique name="uniqueItem"> <xs:selector xpath="item"/> <xs:field xpath="key"/> </xs:unique> </xs:element> </xs:schema> 

For the second:

 <?xml version="1.0" encoding="utf-8"?> <xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:element name="root"> <xs:complexType> <xs:sequence> <xs:element maxOccurs="unbounded" name="item"> <xs:complexType> <xs:attribute name="key" type="xs:string" use="required" /> <xs:attribute name="value" type="xs:string" use="required" /> </xs:complexType> </xs:element> </xs:sequence> </xs:complexType> <xs:unique name="uniqueItem"> <xs:selector xpath="item"/> <xs:field xpath="@key"/> </xs:unique> </xs:element> </xs:schema> 

For the third:

 <?xml version="1.0" encoding="utf-8"?> <xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:element name="root"> <xs:complexType> <xs:sequence> <xs:element name="a" type="xs:string" /> <xs:element name="b" type="xs:string" /> </xs:sequence> </xs:complexType> </xs:element> </xs:schema>