self is used to refer to the current instance where you use it.

This operator can only be used with calculated information.


CONCAT(self.last_name, ", ", self.first_name)

This expression calculates the full name of a person, by getting the information from the fields last_name and first_name, separating those using a comma and a space.

If the expression is attached to an instance of the ‘Person’ ontology, self tells the system to look for the fields last and first name within that instance.

If there, it finds the field last_name holds the value 'Johansdottir' and first_name holds 'Britta', this expression has as output: Johansdottir, Britta