text: <?xml version="1.0" encoding="UTF-8"?>
  <doctrine-mongo-mapping xmlns="http://doctrine-project.org/schemas/odm/doctrine-mongo-mapping"
                    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                    xsi:schemaLocation="http://doctrine-project.org/schemas/odm/doctrine-mongo-mapping
                    http://doctrine-project.org/schemas/odm/doctrine-mongo-mapping.xsd">
  
      <mapped-superclass name="Spy\TimelineBundle\Document\Component">
          <field name="model" fieldName="model" type="string" />
          <field name="identifier" fieldName="identifier" type="string" />
          <field name="hash" fieldName="hash" type="string" />
          <indexes>
              <index>
                  <key name="model" order="asc" />
                  <key name="identifier" order="asc" />
              </index>
              <index unique="true">
                  <key name="hash" order="asc" />
              </index>
          </indexes>
      </mapped-superclass>
  </doctrine-mongo-mapping>
  