Capture date of 'Today' in custom attributre

Summary

We would like to build a rule based on the date 'today' an have that attribute change every day to reflect current date.

Content

Hello, 

Using SQL as the default type, I have an attribute set to default a value of 'Today'. The code runs once, and only runs when we open the attribute group. The return value becomes a static value in the attribute, where we would like it to be dynamic.  

Example: 

I open Item ABC on 4/5 and see 4/5 in the attribute. This is what I was expecting. 

I open Item ABC on 4/6 and still see 4/5 in the attribute. This is not what I was expecting. I would like it to show 4/6 when opened on 4/6 etc...