Check query used to create system views

Question

Hi Group,
I would like to know if there is any way to check the TSQL query used by SQL to create system views. I know for user created views, you can open it in Designer or script the view. Use SQL 2012 as an example when selelcting the top 1000 records no underlyng
query is visible.
Thanks and Regards,

Answer 1

You can see most of them using sys.all_objects and sys.system_sql_modules.  For example
select o.name, m.definition
from sys.system_sql_modules m
inner join sys.all_objects o on m.object_id = o.object_id
where o.name = 'dm_exec_requests'
Be very careful that you don't ever run the code that creates the view.  There are additional tricks behind the scene that give some system views special actions.  So if you run the code, your code might not work the same way as the original system
view.
Also, anything which is not documented can be changed by Microsoft at any time.
Tom