The max value of Null

Nulls are always hot to discuss, especially as it often ends up being something DBA's and developers can argue about for entire lifetimes. Surprisingly few lifetimes are shortened because a DBA and a developer get into a fight over the Very Important Topic of ... Nothing/Null.

Well, two recent examples on how to handle nulls in important systems are so funny that I have to tell them, then I shall say no more on this topic. After all, Chris Date has written entire books on the topic, while another good friend, Lex de Haan, somehow restricts himself to entire days of the (three-valued) logic of Nulls.

First Case: A huge, public system is based on a system developed for another database than Oracle, and so the whole application is made "database independant".

I quoted Jonathan Lewis' chapter 10 of Tales of The OakTable where he says that only many users or much data will create problems for database-independant designs, and since this system will be big and busy, it should be fun to watch in the decades to come.

For one thing, no RI stuff was implemented using the standard SQL way of doing so. After all, who needs PK, FK, and all the rest when you can - hold on to your tables and chairs - can implement the whole thing using PL/SQL in triggers and procedures. Hey, never mind the famous /*+ no_trigger */ hint available in some versions. We're going on that picnic.

Second, nulls were implemented as 192 blanks. No, I'm not drunk and I haven't eaten funny mushrooms. I haven't even had more than a lot of beers in the last hour. 192 blanks it is. Of course I think 192 is a beautiful number, near-perfect, to tell you the truth. But why exactly that number to represent a null value? We'll possibly never know.

Second Case: A DBA told me this story: It had been a long and hard Summer, trying to convince the developers to use, say, only not null columns in primary keys - and not succeding. Well, there were glimpses of hope, they were beginning to understand things about ER diagramming.

That's what the DBA was thinking, hoping, perhaps even believing... until the other day.

The other day one of the developers had come to the DBA with a Very Good Question:

"How do I find the max value of nulls?"

That's when the DBA started crying, left work early, and consumed a bottle of alcohol that night.

/developer/null is the only thing I can add.