A trigger is a repository object that allows you to create an action that happens when a specific event in the repository occurs.
Triggers are attached to link clusters. When the specified event occurs on an active member of the link cluster, the trigger is activated and the specified action occurs. For example, you could create a trigger to send an electronic message to all members of a particular group, when a certain element is edited and checked in to the repository. Triggers are created only by administrators.