Hello all,

Using SQL Server 2000 (Standard Edition, I think).

I was trying to educate myself on creating functions and in one of the examples in Books Online I noticed that you could use
formulas in fields in a table, calculating the field value using other fields as arguments.

My question is this: Is this like a calculated field in a query/view and is recalculated every time the table is opened/queried or
is the field only calculated once during data input and that value is stored in the field?

Thanks for any help anyone can provide,

Conan Kelly

Hey Conan,

Calculated columns are recalculated whenever the underlying data
changes; if you update a value in a column used in the calculated
columns formula, then the data will change.

A couple of notes though:

1. Tables don't have fields; they have columns, rows, and tuples. It
may seem a bit pedantic, but terminology is important.

2. Most implementations of SQL don't use computed columns because it's
a violation of the basic design of a table (look up ACID tests in SQL).
Computed columns can be useful when dealing with large tables (for
performance reasons), but it's one of those things that Microsoft touts
as a great feature, but it really should only be used sparingly.

HTH,
Stu