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Simon Coulter wrote:
This is not an opinion choice nor a business decision. It's a
technical one. If you have a column that can contain NO VALUE then
the correct technical choice is to use NULLs. That's it.
This is the other example of what this list has become. The above
statement is hooey - that's the correct technical term.
Remember, we're not even discussing the null value. No, the focus is on
RPG's particular syntax of the null indicator, which when it boils down
to it is no more than a flag field; just one that can be brought along
from the database by using a few syntactical gyrations.
Think about it - a flag that basically indicates that a single specific
value is in a field. How is that better than simply checking for a
specific value?
The argument has more merit when you abstract it from the RPG
implementation and discuss it purely in the database sense. At that
point, the NULL value does allow some rather arcane behavior in
set-based processing, and if you find yourself in need of summing,
counting and aggregating records in ways that require records to be
eliminated because they have missing values, then you have a good
business case for nulls. Note that this is different than Simon's
assertion above that says simply that if you can have no value, you must
use null. This says that if your business case requires you to omit
records from set-based processing if they are missing values, then null
will make it easier.
Remember, there's nothing magic about null. It's nothing more than a
hidden flag in the database, one that happens to be built into the
ubiquitous SQL syntax. It is not required for a relational database and
indeed some argue against it entirely, while others assert that, like
infinity, there are different orders of null.
It's a tool, and the use of any tool is... a business decision.
Okay, that's 15 minutes wasted. I should be sleeping...
Joe
midrange.com
