Prerequisite: You must be familiar with the Syntax used in Tutorials and have already created an extension.

This use case is just one way of forcing a field to be provided.

For those use cases, we will use UserRequest class, because it has a lifecycle. When an object has a lifecycle, iTop datamodel allow to specify on a Transition and on a State which fields must be required.

Prerequisite: You must be a Combodo's customer

Let's impose that a Service must be documented when a User Request is moved from state New to state Assigned.
That move is called a transition and is uniquely identified by the initial state and the stimulus applied.

Can be done in a few clicks with no code writing

In this usecase we want to be sure that all UserRequest in state Assigned have a Service defined.

Again this is only a few clicks with no code writing

Prerequisite: You must have already created an iTop extension.

Let's impose that a Service must be documented when a User Request is moved from state New to state Assigned.
Here is the XML code you must write for this:

itop_design / classes

    <class id="UserRequest">
      <lifecycle>
        <states>
          <!-- For User Request in State New... -->
          <state id="new">
            <transitions>
              <!-- On the transition, trigger by ev_assign stimulus... -->
              <transition id="ev_assign" _delta="must_exist">
                <flags>
                  <!-- We want to force the Service... -->
                  <attribute id="service_id" _delta="define" >
                    <!-- to be provided -->
                    <mandatory/>
                  </attribute>
                </flags>
              </transition>
            </transitions>
          </state>
        </states>
      </lifecycle>
    </class>

In this usecase we want to be sure that all UserRequest in state Assigned have a Service defined.

itop_design / classes

    <class id="UserRequest" _created_in="itop-request-mgmt-itil" _delta="must_exist">
      <lifecycle>
        <states>
          <state id="assigned" _delta="must_exist">
            <!-- setting no _delta is equivalent to _delta="merge" -->
            <flags>
              <!-- Here we assume that no other extension nor the default datamodel... -->
              <!-- has set flags on field 'service-id' for state 'assigned' already -->
              <attribute id="service_id" _delta="define>
                <mandatory/>
              </attribute>
            </flags>
          </state>
        </states>
      </lifecycle>
    </class>

Migration: No visible effect on setup, but objects not compliant can no more be modified in the Console or Portal, until a Service is provided. Create an audit rule to retrieve objects not compliant to this new constrain and fix them.