Friday, March 30, 2012

Hammers, Rubber Washers, Lug Nuts and Lookup Fields in Tables

Many, many years ago, I learned The First Three Rules of Plumbing.
  1. Never start a plumbing project after all the hardware stores have closed.
  2. Locate the main shut off valve before you start.
  3. A hammer is not a good tool for changing rubber washers in a faucet in the kitchen sink.
You can probably guess how I came by that wisdom, so I'll spare you the details. I can assure you, though, The First Three Rules of Plumbing are not theoretical constructs dreamed up over one too many cups of coffee.

Recently, I was fortunate enough to be able to add The First Three Rules of Tire Repair to my little stock of do-it-yourself wisdom. However, I was able to learn this rule vicariously, rather than through direct experience. I regard that achievement as a mark of growing maturity on my part. I no longer need to smash up my own car or the kitchen sink in order to learn valuable lessons.

Here's how that lesson goes. A young man, long on arm strength and short on disposable cash, needed to change a tire on his car. Having no previous experience with such tasks, he grabbed for the handiest tool; that tool being the very same hammer used in the First Three Rules of Plumbing. A few hefty blows to the first lug nut on that tire snapped it off cleanly. Pleased with his immediate success, this young man rapidly smashed off the remaining lug nuts. At that point, the young man had achieved the first step in his plan, removing the tire  from the car. Fortunately, both the tire and the car fell almost harmlessly to the ground, failing to hit the young man on the way down. The only casualty was his beer, which was crushed by the brake drum that landed on it.

At this point the young man realized the significance of Tire Repair Rule Number One.

1. Don't stand, lie, or sit under or near the car when it collapses during repairs.

Luckily he also learned this lesson vicariously and lost no appendages in the process.

The young man then picked up the dismounted tire and started out for the local garage to have it repaired. He'd only taken a few halting steps when The Second Rule of Tire Repairs came to him.

2. Don't disable your car before you drive to the garage.

Humbled, but not broken, he carried the tire back to the car with the intention of reattaching the tire for the drive to the garage. At that point, The Third Rule of Tire Repairs was revealed to him.

3. A hammer is not a good tool for removing lug nuts.

I'm sure you can think up any number of Repair tasks, in addition to changing faucet washers and removing tires, where a hammer is just about the last tool you want to use. That doesn't mean that all hammers are bad, nor does it imply that hammers have no useful purpose. It just means you should exercise good judgment about when to use one, and when not to use it.

I have now acquired two highly similar sets of Rules for common household repairs task. Although they are separated in time by a few decades of other experiences, the similarities between them did not escape my notice.

This has led me to postulate the Grover Park George Corollary to Abraham H. Maslow's observation on hammers.

Mr. Maslow famously said, "To the [person] who only has a hammer, everything he encounters begins to look like a nail."

The Grover Park George Corollary on Hammering states:

"If you only have a hammer, don't try your hand at do-it-yourself repairs. Hire an expert and pay him to bring his own tools."

Ostensibly, this is a blog about Microsoft Access and my experience using it. So here's how the First Three Rules apply to designing and building database tables.

In my opinion, Lookup Fields in Tables are the Hammers in the Access developers' tool kit.

Lookup fields have their place, to be sure. They are the ONLY way you can define relationships in tables you intend to publish to SharePoint in a web-enabled database. And then, there's.... Let's see, where else? Hm. I guess that's about it.

Anywhere else you are tempted to use a lookup field in a table in Access, please remember the Grover Park George Corollary on Hammering.

You don't want your tables to fall over and crush your beers do you? And you certainly don't want to flood your kitchen at 10:30 on a Friday night when your spouse is already just a little bit irritated by loud pounding coming from the kitchen.