About Global Variables
A global variable is a column created by combining a specific data type with a value. The value can be a Date, Date and Time, Number, Text, and Time.
The global variable is evaluated at the time the analysis is executed, and the value of the global variable is substituted appropriately.
Only users with the BI Service Administrator role can manage (add, edit, and delete) global variables.
You create a global value during the process of creating an analysis by using the Edit Column Formula dialog. The global variable is then saved in the catalog and made available to all other analyses within a specific tenant system.