Two questions:

1) Have you considered using Common Table Expressions?

2) Why would you need to store calculated values?

Using your favourite XML/XML Schema editor you should design an appropriate XML Schema and then import it into your database as an XML SCHEMA COLLECTION.

You can then reference the schema...

So the CREATE USER event was simply a distraction? Tricky, tricky, tricky...

Anyway, you must agree that the CREATE USER event can only have...

From Books Online:

"Returns the current value of the TEXTSIZE option of the SET statement. This specifies the maximum length, in bytes, of varchar(max), nvarchar(max), varbinary(max), text, or image data that...

The EXTERNAL_ACCESS privilege must be granted to a database user that maps to a WindowsNT user. Usually, this is the SQL Service account.

This, of course, may be a security risk => consult...