Make an xsd element mandatory

Question

I have an xml file that I am trying to validate against an xsd file. Works fine. I want to modify the xsd to make an element value mandatory. How do I do this so when I validate

Answer 1

Mandatory

Attribute minOccurs Optional. Specifies the minimum number of times the any element can occur in the parent element. The value can be any number >= 0. Default value is 1. (By default is mandatory)

<!-- mandatory true-->
<xs:element name="lastName" type="xs:string" />
<!-- mandatory false-->
<xs:element name="lastName" type="xs:string" minOccurs="0" />

Not Empty

<xs:element name="lastName" type="xs:string" >
  <xs:simpleType>
     <xs:restriction base="xs:string">
       <xs:minLength value="1"/>
     </xs:restriction>
  </xs:simpleType>
</xs:element>