When does value template get triggered?

Question

Hi, 
 We are working with Value Templates and would like to know under what all conditions does a template get triggered and where can we change that, if possible? 
 For example, the template for Person.CentralAccount makes use of Person.FirstName and Person.LastName. If the value of LastName for an employee is changed, the value for CentralAccount changes. Which means that the template for Person.CentralAccount is executed if LastName or FirstName is changed. Can we prevent the CentralAccount template from executing on change of FirstName and LastName? How can we do this? 
 
 Thanks for your help in advance.

Barry Jackson · Accepted Answer

Hi, 
 All templates are triggered based on changes to referenced attributes. This includes attributes that are explicitly referenced (using the $ notation) and even attributes referenced in VB.Net comment lines (prefixed by a ' [single quote]). 
 If you want the template to only fire once and never again, then uncheck the 'overwrites' checkbox. 
 But be aware ... you may get some undesired side effects .... for example if the template builds centralaccount from firstname and lastname ..... it may only trigger when one of the attributes is populated and it may not trigger again when the other attribute is populated. You'll have to figure this out in testing. 
 HTH, Barry.

Markus Weiss-Ehlers · Answer

You can use the local object meta values to achieve what you want. 
 Please check the following online documentation section http://documents.software.dell.com/identity-manager/7.0.1/configuration-guide/scripts-in-one-identity-manager/using-dollar-$-notation/accessing-local-object-meta-values 
 Four your case: 
 
 Activate the IsOverwriting flag again for the template. 
 Add a condition to your template that checks if the object was loaded from the database and if so do not execute the template. Condition would be 
 
 If NOT $[IsLoaded]:Bool$ Then 
 ... ' Do Something 
 End If

Markus Weiss-Ehlers · Answer

In short, you can't. 
 The notifications to trigger the value template generation require that your tables are connected in a way that a $FK(...).$FK(...)... look-up would be able to find the value. 
 In your case, when I am understanding it correctly, you need to change the value in your custom column for many objects when the value in the referring table has changed. 
 For that use-case you have two options: 
 
 Asynchronous: Create a process chain that will be triggered by the UPDATE event of your referring table. In the process create a process step that uses the task ExecuteTemplates to re-executes the templates for the objects that are related to the changed value of your referring table. You can limit the template execution to your custom column by specifying the process step parameter Columns . 
 Synchronous: Re-execute the templates for the objects that are related to the changed value of your referring table in the OnSaved script of your referring table. Be aware that the save operation for your referring table could run for a long time if you have many object to execute the templates for. 
 
 To prevent any long-running save operations for your referring table I would opt for the asynchronous method.