The ID gives the full path to a [[block]] through the hierarchy of [[sub-system|sub-systems]] that contain it. 

The ID consists of the [[name]] of the [[block]] and the ID of its [[parent|parent sub-system]]. 

For example, with a hierarchy where the [[sub-system]] _France_ contains the sub-system _Paris_ which in turn contains the [[expression]] _Price_ their ID's are:

^Type^Name^ID^
|Sub-system|France|France|
|Sub-system|Paris|France.Paris|
|Expression|Price|France.Paris.Price|

The ID of an object must be **unique** in the [[project]]. 

====See also====

  * [[Name]]
  * [[Sub-system]]