Compilar esquemas XML

Artículo
04/27/2011

Las clases del espacio de nombres System.Xml.Schema se asignan a las estructuras definidas en la recomendación de esquemas XML del W3C (World Wide Web Consortium) y se pueden utilizar para compilar esquemas XML en memoria.

Compilar un esquema XML

En el código de ejemplo que se incluye a continuación, la API del SOM se utiliza para compilar un esquema XML del cliente en memoria.

Creación de elementos y atributos

En el código de ejemplo, se compila el esquema del cliente de abajo arriba, creando primero los elementos secundarios, atributos y sus tipos correspondientes y, a continuación, los elementos de nivel superior.

En el siguiente código de ejemplo, se crean los elementos FirstName y LastName, así como el atributo CustomerId del esquema del cliente utilizando las clases XmlSchemaElement y XmlSchemaAttribute del SOM. Aparte de las propiedades Name de las clases XmlSchemaElement y XmlSchemaAttribute, que se corresponden al atributo "name" de los elementos <xs:element /> y <xs:attribute /> de un esquema XML, todos los demás atributos que permite el esquema (defaultValue, fixedValue, form, etc.) tienen propiedades correspondientes en las clases XmlSchemaElement y XmlSchemaAttribute.

' Create the FirstName and LastName elements.
Dim firstNameElement As XmlSchemaElement = New XmlSchemaElement()
firstNameElement.Name = "FirstName"
Dim lastNameElement As XmlSchemaElement = New XmlSchemaElement()
lastNameElement.Name = "LastName"

' Create CustomerId attribute.
Dim idAttribute As XmlSchemaAttribute = New XmlSchemaAttribute()
idAttribute.Name = "CustomerId"
idAttribute.Use = XmlSchemaUse.Required

// Create the FirstName and LastName elements.
XmlSchemaElement firstNameElement = new XmlSchemaElement();
firstNameElement.Name = "FirstName";
XmlSchemaElement lastNameElement = new XmlSchemaElement();
lastNameElement.Name = "LastName";

// Create CustomerId attribute.
XmlSchemaAttribute idAttribute = new XmlSchemaAttribute();
idAttribute.Name = "CustomerId";
idAttribute.Use = XmlSchemaUse.Required;

        // Create the FirstName and LastName elements.
        XmlSchemaElement^ firstNameElement = gcnew XmlSchemaElement();
        firstNameElement->Name = "FirstName";
        XmlSchemaElement^ lastNameElement = gcnew XmlSchemaElement();
        lastNameElement->Name = "LastName";

        // Create CustomerId attribute.
        XmlSchemaAttribute^ idAttribute = gcnew XmlSchemaAttribute();
        idAttribute->Name = "CustomerId";
        idAttribute->Use = XmlSchemaUse::Required;

Creación de tipos de esquemas

El contenido de los elementos y atributos está definido por sus tipos. Para crear elementos y atributos cuyos tipos sean uno de los tipos de esquemas integrados, la propiedad SchemaTypeName de las clases XmlSchemaElement o XmlSchemaAttribute se establece con el nombre completo correspondiente del tipo integrado utilizando la clase XmlQualifiedName. Para crear un tipo definido por el usuario para elementos y atributos, se crea un nuevo tipo simple o complejo utilizando la clase XmlSchemaSimpleType o XmlSchemaComplexType.

Nota
Para crear tipos simples o complejos sin nombre que sean elementos secundarios anónimos de un elemento o atributo (para los atributos sólo se aplican tipos simples), establezca la propiedad SchemaType de las clases XmlSchemaElement o XmlSchemaAttribute en el tipo simple o complejo sin nombre, en lugar de la propiedad SchemaTypeName de las clases XmlSchemaElement o XmlSchemaAttribute.

Los esquemas XML permiten derivar por restricción tipos simples con nombre y anónimos de otros tipos simples (integrados o definidos por el usuario) o crearlos como una lista o unión de otros tipos simples. La clase XmlSchemaSimpleTypeRestriction se utiliza para crear un tipo simple restringiendo el tipo xs:string integrado. Puede utilizar también las clases XmlSchemaSimpleTypeList o XmlSchemaSimpleTypeUnion para crear tipos de lista o unión. La propiedad XmlSchemaSimpleType.Content indica si se trata de una unión, lista o restricción de tipo simple.

En el siguiente código de ejemplo, el tipo del elemento FirstName es el tipo integrado xs:string, el tipo del elemento LastName es un tipo simple con nombre que es una restricción del tipo integrado xs:string, con un valor de faceta MaxLength de 20 y el tipo del atributo CustomerId es el tipo integrado xs:positiveInteger. El elemento Customer es un tipo complejo anónimo cuya partícula es la secuencia de los elementos FirstName y LastName y cuyos atributos contienen el atributo CustomerId.

Nota
También puede utilizar las clases XmlSchemaChoice o XmlSchemaAll como partícula del tipo complejo para replicar la semántica de <xs:choice /> o <xs:all />.

' Create the simple type for the LastName element.
Dim lastNameType As XmlSchemaSimpleType = New XmlSchemaSimpleType()
lastNameType.Name = "LastNameType"
Dim lastNameRestriction As XmlSchemaSimpleTypeRestriction = _
    New XmlSchemaSimpleTypeRestriction()
lastNameRestriction.BaseTypeName = _
    New XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema")
Dim maxLength As XmlSchemaMaxLengthFacet = New XmlSchemaMaxLengthFacet()
maxLength.Value = "20"
lastNameRestriction.Facets.Add(maxLength)
lastNameType.Content = lastNameRestriction

' Associate the elements and attributes with their types.
' Built-in type.
firstNameElement.SchemaTypeName = _
    New XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema")
' User-defined type.
lastNameElement.SchemaTypeName = _
    New XmlQualifiedName("LastNameType", "http://www.tempuri.org")
' Built-in type.
idAttribute.SchemaTypeName = New XmlQualifiedName("positiveInteger", _
    "http://www.w3.org/2001/XMLSchema")

' Create the top-level Customer element.
Dim customerElement As XmlSchemaElement = New XmlSchemaElement()
customerElement.Name = "Customer"

' Create an anonymous complex type for the Customer element.
Dim customerType As XmlSchemaComplexType = New XmlSchemaComplexType()
Dim sequence As XmlSchemaSequence = New XmlSchemaSequence()
sequence.Items.Add(firstNameElement)
sequence.Items.Add(lastNameElement)
customerType.Particle = sequence

' Add the CustomerId attribute to the complex type.
customerType.Attributes.Add(idAttribute)

' Set the SchemaType of the Customer element to
' the anonymous complex type created above.
customerElement.SchemaType = customerType

// Create the simple type for the LastName element.
XmlSchemaSimpleType lastNameType = new XmlSchemaSimpleType();
lastNameType.Name = "LastNameType";
XmlSchemaSimpleTypeRestriction lastNameRestriction =
    new XmlSchemaSimpleTypeRestriction();
lastNameRestriction.BaseTypeName =
    new XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema");
XmlSchemaMaxLengthFacet maxLength = new XmlSchemaMaxLengthFacet();
maxLength.Value = "20";
lastNameRestriction.Facets.Add(maxLength);
lastNameType.Content = lastNameRestriction;

// Associate the elements and attributes with their types.
// Built-in type.
firstNameElement.SchemaTypeName =
    new XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema");
// User-defined type.
lastNameElement.SchemaTypeName =
    new XmlQualifiedName("LastNameType", "http://www.tempuri.org");
// Built-in type.
idAttribute.SchemaTypeName = new XmlQualifiedName("positiveInteger",
    "http://www.w3.org/2001/XMLSchema");

// Create the top-level Customer element.
XmlSchemaElement customerElement = new XmlSchemaElement();
customerElement.Name = "Customer";

// Create an anonymous complex type for the Customer element.
XmlSchemaComplexType customerType = new XmlSchemaComplexType();
XmlSchemaSequence sequence = new XmlSchemaSequence();
sequence.Items.Add(firstNameElement);
sequence.Items.Add(lastNameElement);
customerType.Particle = sequence;

// Add the CustomerId attribute to the complex type.
customerType.Attributes.Add(idAttribute);

// Set the SchemaType of the Customer element to
// the anonymous complex type created above.
customerElement.SchemaType = customerType;

// Create the simple type for the LastName element.
XmlSchemaSimpleType^ lastNameType = gcnew XmlSchemaSimpleType();
lastNameType->Name = "LastNameType";
XmlSchemaSimpleTypeRestriction^ lastNameRestriction =
    gcnew XmlSchemaSimpleTypeRestriction();
lastNameRestriction->BaseTypeName =
    gcnew XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema");
XmlSchemaMaxLengthFacet^ maxLength = gcnew XmlSchemaMaxLengthFacet();
maxLength->Value = "20";
lastNameRestriction->Facets->Add(maxLength);
lastNameType->Content = lastNameRestriction;

// Associate the elements and attributes with their types.
// Built-in type.
firstNameElement->SchemaTypeName =
    gcnew XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema");
// User-defined type.
lastNameElement->SchemaTypeName =
    gcnew XmlQualifiedName("LastNameType", "http://www.tempuri.org");
// Built-in type.
idAttribute->SchemaTypeName = gcnew XmlQualifiedName("positiveInteger",
    "http://www.w3.org/2001/XMLSchema");

// Create the top-level Customer element.
XmlSchemaElement^ customerElement = gcnew XmlSchemaElement();
customerElement->Name = "Customer";

// Create an anonymous complex type for the Customer element.
XmlSchemaComplexType^ customerType = gcnew XmlSchemaComplexType();
XmlSchemaSequence^ sequence = gcnew XmlSchemaSequence();
sequence->Items->Add(firstNameElement);
sequence->Items->Add(lastNameElement);
customerType->Particle = sequence;

// Add the CustomerId attribute to the complex type.
customerType->Attributes->Add(idAttribute);

// Set the SchemaType of the Customer element to
// the anonymous complex type created above.
customerElement->SchemaType = customerType;

Creación y compilación de esquemas

En este punto, los atributos y elementos secundarios, sus tipos correspondientes y el elemento Customer de nivel superior se han creado en memoria utilizando la API del SOM. En el siguiente código de ejemplo, el elemento de esquema se crea utilizando la clase XmlSchema, los tipos y elementos de nivel superior se agregan a él utilizando la propiedad XmlSchema.Items y el esquema completo se compila utilizando la clase XmlSchemaSet y se escribe en la consola.

' Create an empty schema.
Dim customerSchema As XmlSchema = New XmlSchema()
customerSchema.TargetNamespace = "http://www.tempuri.org"

' Add all top-level element and types to the schema
customerSchema.Items.Add(customerElement)
customerSchema.Items.Add(lastNameType)

' Create an XmlSchemaSet to compile the customer schema.
Dim schemaSet As XmlSchemaSet = New XmlSchemaSet()
AddHandler schemaSet.ValidationEventHandler, AddressOf ValidationCallback
schemaSet.Add(customerSchema)
schemaSet.Compile()

For Each schema As XmlSchema In schemaSet.Schemas()
    customerSchema = schema
Next

' Write the complete schema to the Console.
customerSchema.Write(Console.Out)

// Create an empty schema.
XmlSchema customerSchema = new XmlSchema();
customerSchema.TargetNamespace = "http://www.tempuri.org";

// Add all top-level element and types to the schema
customerSchema.Items.Add(customerElement);
customerSchema.Items.Add(lastNameType);

// Create an XmlSchemaSet to compile the customer schema.
XmlSchemaSet schemaSet = new XmlSchemaSet();
schemaSet.ValidationEventHandler += new ValidationEventHandler(ValidationCallback);
schemaSet.Add(customerSchema);
schemaSet.Compile();

foreach (XmlSchema schema in schemaSet.Schemas())
{
    customerSchema = schema;
}

// Write the complete schema to the Console.
customerSchema.Write(Console.Out);

// Create an empty schema.
XmlSchema^ customerSchema = gcnew XmlSchema();
customerSchema->TargetNamespace = "http://www.tempuri.org";

// Add all top-level element and types to the schema
customerSchema->Items->Add(customerElement);
customerSchema->Items->Add(lastNameType);

// Create an XmlSchemaSet to compile the customer schema.
XmlSchemaSet^ schemaSet = gcnew XmlSchemaSet();
schemaSet->ValidationEventHandler += gcnew ValidationEventHandler(ValidationCallback);
schemaSet->Add(customerSchema);
schemaSet->Compile();

for each (XmlSchema^ schema in schemaSet->Schemas())
{
    customerSchema = schema;
}

// Write the complete schema to the Console.
customerSchema->Write(Console::Out);

El método XmlSchemaSet.Compile valida el esquema del cliente con las reglas de un esquema XML y hace que las propiedades posteriores a la compilación del esquema estén disponibles.

Nota
Todas las propiedades posteriores a la compilación del esquema de la API del SOM son diferentes a las del conjunto de información posterior a la validación del esquema.

El ValidationEventHandler que se agrega al XmlSchemaSet es un delegado que llama al método de devolución de llamada ValidationCallback para controlar los errores y advertencias de validación de esquemas.

A continuación, se ofrece el código de ejemplo completo y el esquema del cliente escrito en la consola.

Imports System
Imports System.Xml
Imports System.Xml.Schema

Class XmlSchemaCreateExample

    Shared Sub Main()

        ' Create the FirstName and LastName elements.
        Dim firstNameElement As XmlSchemaElement = New XmlSchemaElement()
        firstNameElement.Name = "FirstName"
        Dim lastNameElement As XmlSchemaElement = New XmlSchemaElement()
        lastNameElement.Name = "LastName"

        ' Create CustomerId attribute.
        Dim idAttribute As XmlSchemaAttribute = New XmlSchemaAttribute()
        idAttribute.Name = "CustomerId"
        idAttribute.Use = XmlSchemaUse.Required

        ' Create the simple type for the LastName element.
        Dim lastNameType As XmlSchemaSimpleType = New XmlSchemaSimpleType()
        lastNameType.Name = "LastNameType"
        Dim lastNameRestriction As XmlSchemaSimpleTypeRestriction = _
            New XmlSchemaSimpleTypeRestriction()
        lastNameRestriction.BaseTypeName = _
            New XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema")
        Dim maxLength As XmlSchemaMaxLengthFacet = New XmlSchemaMaxLengthFacet()
        maxLength.Value = "20"
        lastNameRestriction.Facets.Add(maxLength)
        lastNameType.Content = lastNameRestriction

        ' Associate the elements and attributes with their types.
        ' Built-in type.
        firstNameElement.SchemaTypeName = _
            New XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema")
        ' User-defined type.
        lastNameElement.SchemaTypeName = _
            New XmlQualifiedName("LastNameType", "http://www.tempuri.org")
        ' Built-in type.
        idAttribute.SchemaTypeName = New XmlQualifiedName("positiveInteger", _
            "http://www.w3.org/2001/XMLSchema")

        ' Create the top-level Customer element.
        Dim customerElement As XmlSchemaElement = New XmlSchemaElement()
        customerElement.Name = "Customer"

        ' Create an anonymous complex type for the Customer element.
        Dim customerType As XmlSchemaComplexType = New XmlSchemaComplexType()
        Dim sequence As XmlSchemaSequence = New XmlSchemaSequence()
        sequence.Items.Add(firstNameElement)
        sequence.Items.Add(lastNameElement)
        customerType.Particle = sequence

        ' Add the CustomerId attribute to the complex type.
        customerType.Attributes.Add(idAttribute)

        ' Set the SchemaType of the Customer element to
        ' the anonymous complex type created above.
        customerElement.SchemaType = customerType

        ' Create an empty schema.
        Dim customerSchema As XmlSchema = New XmlSchema()
        customerSchema.TargetNamespace = "http://www.tempuri.org"

        ' Add all top-level element and types to the schema
        customerSchema.Items.Add(customerElement)
        customerSchema.Items.Add(lastNameType)

        ' Create an XmlSchemaSet to compile the customer schema.
        Dim schemaSet As XmlSchemaSet = New XmlSchemaSet()
        AddHandler schemaSet.ValidationEventHandler, AddressOf ValidationCallback
        schemaSet.Add(customerSchema)
        schemaSet.Compile()

        For Each schema As XmlSchema In schemaSet.Schemas()
            customerSchema = schema
        Next

        ' Write the complete schema to the Console.
        customerSchema.Write(Console.Out)
    End Sub

    Shared Sub ValidationCallback(ByVal sender As Object, ByVal args As ValidationEventArgs)
        If args.Severity = XmlSeverityType.Warning Then
            Console.Write("WARNING: ")
        Else
            If args.Severity = XmlSeverityType.Error Then
                Console.Write("ERROR: ")
            End If
        End If
        Console.WriteLine(args.Message)
    End Sub
End Class

using System;
using System.Xml;
using System.Xml.Schema;

class XmlSchemaCreateExample
{
    static void Main(string[] args)
    {
        // Create the FirstName and LastName elements.
        XmlSchemaElement firstNameElement = new XmlSchemaElement();
        firstNameElement.Name = "FirstName";
        XmlSchemaElement lastNameElement = new XmlSchemaElement();
        lastNameElement.Name = "LastName";

        // Create CustomerId attribute.
        XmlSchemaAttribute idAttribute = new XmlSchemaAttribute();
        idAttribute.Name = "CustomerId";
        idAttribute.Use = XmlSchemaUse.Required;

        // Create the simple type for the LastName element.
        XmlSchemaSimpleType lastNameType = new XmlSchemaSimpleType();
        lastNameType.Name = "LastNameType";
        XmlSchemaSimpleTypeRestriction lastNameRestriction =
            new XmlSchemaSimpleTypeRestriction();
        lastNameRestriction.BaseTypeName =
            new XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema");
        XmlSchemaMaxLengthFacet maxLength = new XmlSchemaMaxLengthFacet();
        maxLength.Value = "20";
        lastNameRestriction.Facets.Add(maxLength);
        lastNameType.Content = lastNameRestriction;

        // Associate the elements and attributes with their types.
        // Built-in type.
        firstNameElement.SchemaTypeName =
            new XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema");
        // User-defined type.
        lastNameElement.SchemaTypeName =
            new XmlQualifiedName("LastNameType", "http://www.tempuri.org");
        // Built-in type.
        idAttribute.SchemaTypeName = new XmlQualifiedName("positiveInteger",
            "http://www.w3.org/2001/XMLSchema");

        // Create the top-level Customer element.
        XmlSchemaElement customerElement = new XmlSchemaElement();
        customerElement.Name = "Customer";

        // Create an anonymous complex type for the Customer element.
        XmlSchemaComplexType customerType = new XmlSchemaComplexType();
        XmlSchemaSequence sequence = new XmlSchemaSequence();
        sequence.Items.Add(firstNameElement);
        sequence.Items.Add(lastNameElement);
        customerType.Particle = sequence;

        // Add the CustomerId attribute to the complex type.
        customerType.Attributes.Add(idAttribute);

        // Set the SchemaType of the Customer element to
        // the anonymous complex type created above.
        customerElement.SchemaType = customerType;

        // Create an empty schema.
        XmlSchema customerSchema = new XmlSchema();
        customerSchema.TargetNamespace = "http://www.tempuri.org";

        // Add all top-level element and types to the schema
        customerSchema.Items.Add(customerElement);
        customerSchema.Items.Add(lastNameType);

        // Create an XmlSchemaSet to compile the customer schema.
        XmlSchemaSet schemaSet = new XmlSchemaSet();
        schemaSet.ValidationEventHandler += new ValidationEventHandler(ValidationCallback);
        schemaSet.Add(customerSchema);
        schemaSet.Compile();

        foreach (XmlSchema schema in schemaSet.Schemas())
        {
            customerSchema = schema;
        }

        // Write the complete schema to the Console.
        customerSchema.Write(Console.Out);
    }

    static void ValidationCallback(object sender, ValidationEventArgs args)
    {
        if (args.Severity == XmlSeverityType.Warning)
            Console.Write("WARNING: ");
        else if (args.Severity == XmlSeverityType.Error)
            Console.Write("ERROR: ");

        Console.WriteLine(args.Message);
    }
}

#using <System.Xml.dll>

using namespace System;
using namespace System::Xml;
using namespace System::Xml::Schema;

ref class XmlSchemaCreateExample
{
public:

    static void Main()
    {
        // Create the FirstName and LastName elements.
        XmlSchemaElement^ firstNameElement = gcnew XmlSchemaElement();
        firstNameElement->Name = "FirstName";
        XmlSchemaElement^ lastNameElement = gcnew XmlSchemaElement();
        lastNameElement->Name = "LastName";

        // Create CustomerId attribute.
        XmlSchemaAttribute^ idAttribute = gcnew XmlSchemaAttribute();
        idAttribute->Name = "CustomerId";
        idAttribute->Use = XmlSchemaUse::Required;

        // Create the simple type for the LastName element.
        XmlSchemaSimpleType^ lastNameType = gcnew XmlSchemaSimpleType();
        lastNameType->Name = "LastNameType";
        XmlSchemaSimpleTypeRestriction^ lastNameRestriction =
            gcnew XmlSchemaSimpleTypeRestriction();
        lastNameRestriction->BaseTypeName =
            gcnew XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema");
        XmlSchemaMaxLengthFacet^ maxLength = gcnew XmlSchemaMaxLengthFacet();
        maxLength->Value = "20";
        lastNameRestriction->Facets->Add(maxLength);
        lastNameType->Content = lastNameRestriction;

        // Associate the elements and attributes with their types.
        // Built-in type.
        firstNameElement->SchemaTypeName =
            gcnew XmlQualifiedName("string", "http://www.w3.org/2001/XMLSchema");
        // User-defined type.
        lastNameElement->SchemaTypeName =
            gcnew XmlQualifiedName("LastNameType", "http://www.tempuri.org");
        // Built-in type.
        idAttribute->SchemaTypeName = gcnew XmlQualifiedName("positiveInteger",
            "http://www.w3.org/2001/XMLSchema");

        // Create the top-level Customer element.
        XmlSchemaElement^ customerElement = gcnew XmlSchemaElement();
        customerElement->Name = "Customer";

        // Create an anonymous complex type for the Customer element.
        XmlSchemaComplexType^ customerType = gcnew XmlSchemaComplexType();
        XmlSchemaSequence^ sequence = gcnew XmlSchemaSequence();
        sequence->Items->Add(firstNameElement);
        sequence->Items->Add(lastNameElement);
        customerType->Particle = sequence;

        // Add the CustomerId attribute to the complex type.
        customerType->Attributes->Add(idAttribute);

        // Set the SchemaType of the Customer element to
        // the anonymous complex type created above.
        customerElement->SchemaType = customerType;

        // Create an empty schema.
        XmlSchema^ customerSchema = gcnew XmlSchema();
        customerSchema->TargetNamespace = "http://www.tempuri.org";

        // Add all top-level element and types to the schema
        customerSchema->Items->Add(customerElement);
        customerSchema->Items->Add(lastNameType);

        // Create an XmlSchemaSet to compile the customer schema.
        XmlSchemaSet^ schemaSet = gcnew XmlSchemaSet();
        schemaSet->ValidationEventHandler += gcnew ValidationEventHandler(ValidationCallback);
        schemaSet->Add(customerSchema);
        schemaSet->Compile();

        for each (XmlSchema^ schema in schemaSet->Schemas())
        {
            customerSchema = schema;
        }

        // Write the complete schema to the Console.
        customerSchema->Write(Console::Out);
    }

    static void ValidationCallback(Object^ sender, ValidationEventArgs^ args)
    {
        if (args->Severity == XmlSeverityType::Warning)
            Console::Write("WARNING: ");
        else if (args->Severity == XmlSeverityType::Error)
            Console::Write("ERROR: ");

        Console::WriteLine(args->Message);
    }
};

int main()
{
    XmlSchemaCreateExample::Main();
    return 0;
}

<?xml version="1.0" encoding="utf-8"?>
<xs:schema xmlns:tns="http://www.tempuri.org" targetNamespace="http://www.tempuri.org" xmlns:xs="http://www.w3.org/2001/XMLSchema">
   <xs:element name="Customer">
      <xs:complexType>
         <xs:sequence>
            <xs:element name="FirstName" type="xs:string" />
            <xs:element name="LastName" type="tns:LastNameType" />
         </xs:sequence>
         <xs:attribute name="CustomerId" type="xs:positiveInteger" use="required" />
      </xs:complexType>
   </xs:element>
   <xs:simpleType name="LastNameType">
      <xs:restriction base="xs:string">
         <xs:maxLength value="20" />
      </xs:restriction>
   </xs:simpleType>
</xs:schema>