From database to XML with data types

I am getting info from a database and adding it to a dataset. Then I create a XML with this info. I would want to have the XML, but also the datatypes in the header. Is it possible? Here my code to write the XML:

//Fill dataset with different datatable:
//first datatable
DataSet imports = new DataSet("import");
NpgsqlDataAdapter daImport = new NpgsqlDataAdapter("select field1, field2 field3 from table1", _connPg);
daImport.FillSchema(imports, SchemaType.Source, "table1");
daImport.Fill(imports, "table1");
//seconda datatable

NpgsqlDataAdapter daImport1 = new NpgsqlDataAdapter("select field1, field2 field3 from table2", _connPg);
daImport1.FillSchema(imports, SchemaType.Source, "table2");
daImport1.Fill(imports, "table2");

//insert relation
DataRelation relation = new DataRelation("rel_rel1", imports.Tables["table1"].Columns["field1"], imports.Tables["table2"].Columns["field2"], true);
relation.Nested = true;
imports.Relations.Add(relation);
//write xml
imports.WriteXml("dataImport.xml");

And this is my xml

<?xml version="1.0" standalone="yes"?>
    <import>
    <table1>
    <field1>1
    </field1>
    <field2>name
    </field2>
    <field3>surname
    </field3>
    <table2>
    <field1>somedata
    </field1>
    <field2>1
    </field2>
    <field3>otherdata
    </field3>
    </table2>
    </table1>
    </import>

What I want? I would want to get this XML but with the types of the fields defined in the header.

Thanks!

If you want the schema to be serialized with the data, just change :

imports.WriteXml("dataImport.xml");

to :

imports.WriteXml("dataImport.xml", XmlWriteMode.WriteSchema);

It will produce the following XML :

<?xml version="1.0" standalone="yes"?>
<import>
  <xs:schema id="import" xmlns="" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
    <xs:element name="import" msdata:IsDataSet="true" msdata:UseCurrentLocale="true">
      <xs:complexType>
        <xs:choice minOccurs="0" maxOccurs="unbounded">
          <xs:element name="table1">
            <xs:complexType>
              <xs:sequence>
                <xs:element name="field1" type="xs:int" />
                <xs:element name="field2" type="xs:string" minOccurs="0" />
                <xs:element name="field3" type="xs:boolean" minOccurs="0" />
                <xs:element name="table2" minOccurs="0" maxOccurs="unbounded">
                  <xs:complexType>
                    <xs:sequence>
                      <xs:element name="field1" type="xs:int" />
                      <xs:element name="field2" type="xs:int" minOccurs="0" />
                      <xs:element name="field3" type="xs:double" minOccurs="0" />
                    </xs:sequence>
                  </xs:complexType>
                </xs:element>
              </xs:sequence>
            </xs:complexType>
          </xs:element>
        </xs:choice>
      </xs:complexType>
      <xs:unique name="table2_Constraint1" msdata:ConstraintName="Constraint1" msdata:PrimaryKey="true">
        <xs:selector xpath=".//table2" />
        <xs:field xpath="field1" />
      </xs:unique>
      <xs:unique name="Constraint1" msdata:PrimaryKey="true">
        <xs:selector xpath=".//table1" />
        <xs:field xpath="field1" />
      </xs:unique>
      <xs:keyref name="FK_T1T2" refer="Constraint1" msdata:IsNested="true">
        <xs:selector xpath=".//table2" />
        <xs:field xpath="field2" />
      </xs:keyref>
    </xs:element>
  </xs:schema>
  <table1>
    <field1>0</field1>
    <field2>test</field2>
    <field3>false</field3>
    <table2>
      <field1>0</field1>
      <field2>0</field2>
      <field3>0</field3>
    </table2>
    <table2>
      <field1>1</field1>
      <field2>0</field2>
      <field3>1.25</field3>
    </table2>
  </table1>
  <table1>
    <field1>1</field1>
    <field2>test 2</field2>
    <field3>true</field3>
  </table1>
  <table1>
    <field1>2</field1>
    <field2>test 3</field2>
    <field3>false</field3>
    <table2>
      <field1>2</field1>
      <field2>2</field2>
      <field3>2.66</field3>
    </table2>
  </table1>
</import>