Figure Proj.04 - element relationships

Following Figure shows how these relationship types are incorporated into the Project model.<br/>The ProjectElementRelationship allows relating ProjectElements. A ProjectElement might be linked to several ProjectElements.<br/>Ex: a ProjectElement not being able to start until another ProjectElement has been completed.<br/>The ProjectElements can be related by two types of relationships: Dependency or Replacement.<br/>A Dependency is where the two Project Elements have some starting or finishing dependency. E.g. Activity 2 cannot start until Activity 1 is complete.<br/>A Replacement is where one or more ProjectElements are replaced by one or more other ProjectElements.<br/>Each type of relationship might be subdivided into several kinds: <br/>The subtypes of Dependency are:<br/><ul>
<li>before-start-delay: Activity2 starts at least “lag” timepoints after Activity1 starts</li><li>before-finish-delay: Activity2 starts at least “lag” timepoints after Activity1 finishes</li><li>after-start-delay: Activity2 finishes at least “lag” timepoints after Activity1 starts</li><li>after-finish-delay: Activity2 finishes at least “lag” timepoints after Activity1 finishes</li><li>start-equal-start: Activity2 starts exactly “lag” timepoints after Activity1 starts</li><li>start-equal-finish: Activity2 starts exactly “lag” timepoints after Activity1 finishes</li><li>finish-equal-start: Activity2 finishes exactly “lag” timepoints after Activity1 starts</li><li>finish-equal-finish : Activity2 finishes exactly “lag” timepoints after Activity1 finishes</li></ul>
The subtypes of Replacement are:<br/><ul>
<li>Substitution: This is a one for one replacement. E.g. Activity 1 is no longer valid and has been replaced by Activity 1A</li><li>Division: This is a one for many replacement. E.g. Activity 1 is no longer valid and has been replaced by Activities 1A, 1B and 1C</li></ul>
Fusion: This is a many for one replacement. E.g. Activities 1A, 1B and 1C are no longer valid and have been replaced by Activity 1Z<br/>