Required Reading

It's not often that I run across articles that really resonate with me. Last night was one of those rare occasions. What follows is a sampling of what I consider to be required reading for any IT professional with a slant towards database development.

• Bad CaRMa
• Big Ball of Mud
• How To Ask Questions The Smart Way
• Business Logic - PL/SQL Vs Java - Reg
• Thinking Clearly About Performance
• The Complicator's Gloves

Bad CaRMa

how NOT to design a database schema - super classic article. Every data architect should read this ! simple-talk.com/opinion/opinio… @timothyjgorman

— Kyle Hailey (@dboptimizer) June 11, 2013

That led me to Bad CaRMa by Tim Gorman. This was an entry in Oracle Insights: Tales of the Oak Table, which I have not read, yet.

A snippet:

...The basic premise was that just about all of the features of the relational database were eschewed, and instead it was used like a filing system for great big plastic bags of data. Why bother with other containers for the data—just jam it into a generic black plastic garbage bag. If all of those bags full of different types of data all look the same and are heaped into the same pile, don't worry! We'll be able to differentiate the data after we pull it off the big pile and look inside.

Amazingly, Randy and his crew thought this was incredibly clever. Database engineer after database engineer were struck dumb by the realization of what Vision was doing, but the builders of the one-table database were blissfully aware that they were ushering in a new dawn in database design...

This is from 2006 (the book was published in 2004). Not sure how I missed that story, but I did.

Big Ball of Mud

I've read this one, and sent it out, many times over the years. I can't remember when I first encountered it, but I read this once every couple of months. I send it out to colleagues about as often. You can find the article here.

A BIG BALL OF MUD is haphazardly structured, sprawling, sloppy, duct-tape and bailing wire, spaghetti code jungle. We’ve all seen them. These systems show unmistakable signs of unregulated growth, and repeated, expedient repair. Information is shared promiscuously among distant elements of the system, often to the point where nearly all the important information becomes global or duplicated. The overall structure of the system may never have been well defined. If it was, it may have eroded beyond recognition. Programmers with a shred of architectural sensibility shun these quagmires. Only those who are unconcerned about architecture, and, perhaps, are comfortable with the inertia of the day-to-day chore of patching the holes in these failing dikes, are content to work on such systems.

Read it. Remember it.

How To Ask Questions The Smart Way

Ever been in a forum? Has anyone ever given you the "RTFM" answer? Here's how you can avoid it. How To Ask Questions The Smart Way. I read this originally about 9 or 10 years ago. I've sent it out countless times.

The first thing to understand is that hackers actually like hard problems and good, thought-provoking questions about them. If we didn't, we wouldn't be here. If you give us an interesting question to chew on we'll be grateful to you; good questions are a stimulus and a gift. Good questions help us develop our understanding, and often reveal problems we might not have noticed or thought about otherwise. Among hackers, “Good question!” is a strong and sincere compliment.

Despite this, hackers have a reputation for meeting simple questions with what looks like hostility or arrogance. It sometimes looks like we're reflexively rude to newbies and the ignorant. But this isn't really true.

What we are, unapologetically, is hostile to people who seem to be unwilling to think or to do their own homework before asking questions. People like that are time sinks — they take without giving back, and they waste time we could have spent on another question more interesting and another person more worthy of an answer. We call people like this “losers” (and for historical reasons we sometimes spell it “lusers”).

Business Logic - PL/SQL Vs Java - Reg

The article can be found here.

I don't believe this is the one that I would read just about every day during my first few years working with Oracle, but it's representative (I'll link up the original when I find it). I cut my teeth in the Oracle world by reading AskTom every single day for years. Some of my work at the time included working with java server pages (jsp) - at least until I found APEX. I monkeyed around with BC4J for awhile as well, but I believe these types of threads on AskTom kept me from going off the cliff. In fact, I got to a point where I would go to an interview and then debate the interviewer about this same topic. Fun times.

if it touches data -- plsql.

If it is computing a fourier transformation -- java.

If it is processing data -- plsql.

If it is generating a graph -- java.

If it is doing a transaction of any size, shape or form against data -- plsql.

Thinking Clearly About Performance

Cary Millsap. Most of the people seem to know Cary from Optimizing Oracle Performance, I didn't. I first "met" Cary virtually and he was gracious enough to help me understand my questions around Logging, Debugging, Instrumentation and Profiling. Anyway, what I've learned over that time, is that Cary doesn't think of himself as a DBA, he's a Developer. That was shocking for me to hear...I wonder how many others know that. So I've read this paper about 20 times over the last couple of years (mostly because I'm a little slow). I organize events around this topic (instrumentation, writing better software, etc) and this fits in perfectly. My goal is to one day co-present with Cary, while playing catch, on this topic (I don't think he knows that, so don't tell him). Link to his paper can be found here. Enjoy!

The Complicator's Gloves

One of my favorite articles from The Daily WTF of all time. Find the article here. The gist of the story is this: an internal forum where people were discussing how to warm a given individuals hands on his bike ride to work. The engineers then proceeded to come up with all kinds of solutions...they spent all day doing this. Finally, someone posts, "wear gloves." End of discussion. Love it. I wrote about it years ago in Keeping it Simple. For a few years I considered buying up thecomplicatorsgloves.com and try to gather related stories, but I got lazy. You should read this often, or better, send it out to colleagues on a regular basis to remind them of their craziness.

I'll continue to add to this list as time goes on. If you have any suggestions, leave a comment and I'll add them to the list.

caveats

I always find myself putting an asterisk (if only mentally) next to certain statements. I shall now put all those statements here and link back.

1. I don't know everything
2. I'm not the best developer in the world, but I constantly work at getting better...
3. If I make a statement about something, that's been my experience. Your results may vary.
4. I am not a salesman.
5. I do not work for <insert company name which I just pitched here>

That's it...for now.

Ubuntu 12.10 + nvidia

I updated my host OS a few months back after getting repeated notifications (yes, I know, I can shut them off) that 10.04 (I think) was moving out of support.

Since then, I've had an issue with my Nvidia drivers. Basically, I get video on a single monitor (dual set up) and that single monitor resolution is like 200 x 400 (no, it's not really that, but it is gigantic). Thank goodness for The Google Machine™. That originally led me here on StackOverflow. (Another reason to do things from the command line, you can remember things with   history | grep nvidia).

I'm on the 4th time of going through this exercise. Each time the kernel is updated, nvidia breaks. Fortunately for me, that guy on StackOverflow gave me all the information I needed. This time after reboot and the gigantic screen, I removed the nvidia drivers and then reinstalled them. No go. uname -r gave me the following: 3.5.0-26-generic and dpkg -l|grep headers showed an older version of the kernel headers. So I updated those, reinstalled nvidia-current and rebooted. Yay.

Many "small" issues like this recently have me pondering a move back to, gasp, Windows or perhaps even a Mac. The Mac ecosystem scares me because it is expensive...but it's difficult to square when so many of my friends (technical and otherwise) swear by Macs. Something for another day I guess...

Fun with CHAR

I'm busy deriving file layouts from PL/SQL. Probably close to 100 file definitions...each of them slightly different, each of them defined in the code. Fun!

There are a mixture of types too, fixed width, csv, etc. Thankfully, I've read enough of the code now that it's relatively easy to figure out. The fixed width variety is what this is about though.

In much of the code, there's a type that's defined, something like this:

type my_record is record
(
  column_01 CHAR(10),
  column_02 CHAR(10),
  column_03 CHAR(10)
);

That's then used to receive assignments from incoming variables. I'll hardcode my variables for this exercise.

declare
  type my_record is record
  (
    column_01 CHAR(10),
    column_02 CHAR(10),
    column_03 CHAR(10)
  );
  l_rec my_record;
begin
  l_rec.column_01 := '1';
  l_rec.column_02 := '3';
  l_rec.column_03 := '6';
end;

Littered throughout those assignments though, are things like LPAD and RPAD. You're going to say, "well, yeah, if it's a number, you may want it right aligned or something." Fair enough. But I'm not talking about those, I'm talking about this:

  l_rec.column_01 := rpad( ' ', 10 );
  l_rec.column_02 := '3';
  l_rec.column_03 := RPAD( ' ', 10 );

Ostensibly, these columns once held data. Instead of forcing the client (application, business, whatever) to change their processing bit, the file was left the same. Makes sense.

Then I started to think about it...it's a CHAR. CHAR is already fixed width. To wit:

drop table t purge;

create table t
(
  x CHAR(10)
);

insert into t ( x ) values ( ' ' );
insert into t ( x ) values ( null );

select 
  rownum, 
  length( x ), 
  x
from t;

    ROWNUM  LENGTH(X) X        
---------- ---------- ----------
         1         10            
         2                       

I inserted a single space in the first record. It has a length of 10 despite only inserting a single character there.

So what's the purpose of those RPAD( ' ', 10 ) calls? I'm not sure.

The only reason I even began to think about it was that I ran across one type set up with VARCHAR data types. There it makes sense, using RPAD I mean. With the CHAR field, it's a waste of typing IMO. Perhaps it was just for readability...who knows?