Is it possible to automatically recalculate calculate fields in an attribute table?

[BobChristensen]

Greetings, 

I have a couple questions about calculating fields in an attribute table. 

First, is it possible to automatically store the expression used to calculate field in the metadata (or does this already happen and I just do not know how to access these records?) so there is a record kept for how fields were calculated?

Second, is it possible to store an expression in a field in such a way that allows for the field to be recalculated when data that the expression pulls from changes?

[DanPatterson_Retired]

Don't know about automatic, but I have gotten into the practice of saving field calculator expressions (complicated ones at least) as *.exp files in the project folder.  You can then reload them as needed.  I normally name them with the fieldname and date.  More generic expressions (ie those involving geometry), I save to a field calculator folder so that I can pull them up all the time.

Mind you, this may seem overly cumbersome, but I learned never to trust 'automagic' anything.

[ThomasColson]

If you're using a SQL Database (Oracle, SQL), then you have quite a few possibilities for automating attribute values. You can do something really over the top like /blogs/HackingArcSDE/2014/12/31/hey-neighbor-whats-your-value , or just add a simple calculated constraint to a column, such as adding an acres field, and using the calculated constraint to update the value based on the shape field.