Description:
If the element files are defined nillable in the schema, we directly set these elements to be empty in the XML data input and an error will be thrown.

How to parse nillable fields in XML.

There are at least two ways to enable the nillable element. One way is by adding the following lines into your schema:

    <xs:element name="NillableDateField" type="xs:dateTime" nillable="true"/>

    <xs:element name="NilableDecimalField" type="xs:decimal" nillable="true"/>

Then in the data input, use the following format:

            <n1:NilableDecimalField xsi:nil="true"/>

            <n1:NillableDateField xsi:nil="true"/>

The other way is to define the schema as follows:

    <xs:simpleType name="decimal-or-empty">
        <xs:union memberTypes="xs:decimal empty-string"/>
    </xs:simpleType>
    <xs:simpleType name="date-or-empty">
        <xs:union memberTypes="xs:date empty-string"/>
    </xs:simpleType>
    <xs:simpleType name="empty-string">
        <xs:restriction base="xs:string">
            <xs:enumeration value=""/>
        </xs:restriction>
    </xs:simpleType>
    <xs:element name="NillableDateField" type="date-or-empty"/>

The input field format can be directly set to be empty:

            <n1:NilableDecimalField/>

            <n1:NillableDateField/>

X3C XML schema part-1