So here is a typical data model pattern:

create table master ( mid int not null auto_increment, … , primary key (mid) );

create table detail ( mid int not null, did int not null auto_increment, … , primary key (mid, did) );

( detail.mid is a foreign key to master.mid but no one uses these in MySQL… )

So this works great if you’re using the default MyISAM storage manager but it does not work using the InnoDB storage manager (RTFM!). Unfortunately, MyISAM does not provide ACID properties which means you should not be using MyISAM unless you have another way of recovering from data loss. My data is valuable so I have to use InnoDB, which means I have to restructure the detail table so that detail.did is the primary key and detail.mid is just a field with an index.

I really wish MySQL had one storage manager that actually worked like a relational database is supposed to, instead of several half-working storage managers.

Did a quick test of 2 PHP IDEs. I wanted to see if anything could be more productive than my current EasyPHP and XEmacs environment. It was partially motivated by the fact that XEmacs for Windows is broken at the moment.

The test was essentially whether I could download the tool and be productive in 20 minutes.

Zend Studio failed the test. I installed Zend Studio Server and then Zend Studio Client. I then tried to edit and debug my large PHP application. I couldn’t figure out where Zend Studio wanted the files to be and gave up after screwing around with it for an hour.

PHPed passed the test. The help file described how to set up debugging (drop a dll into the PHP extensions directory and edit the php.ini file) and I was able to debug code running in EasyPHP in about 5 minutes. The editor itself is a bit sluggish so I may end up editing in emacs and debugging in PHPed.

Update: XEmacs.org posted an installer for the latest version so that php-mode works again. I didn’t end up buying a license for PHPed since I’m such a cheap bastard and I’m really good at debugging code by inserting print statements…

ToDo: Look at PHP Eclipse

Say you are writing a CGI script using the CGI.pm library and you want to pass an argument in the query string. In a normal language, you might write this kind of code to check the query string parameter:

my $arg = param(’arg’);
if ($arg == ‘SOMEVALUE’) {
  # handle the arg…
}

This is pretty much what you write in PHP or Python and it pretty much works as you expect. On planet perl, however, if you don’t supply “arg” in the query string, the if test will evaluate to true. Now if you really know perl, you would know that equality in perl is a slippery concept, like justice. A perl person would say that I’m not supposed to use the ‘==’ operator to compare strings. The ‘==’ operator is used to compare numbers (even if the numbers are strings). And if my numbers are actually strings, perl is clever enough to convert my arguments to numbers for me before doing the compare. So how in the world did a null / empty string end up numerically equal to a non-null / non-empty string?

Until someone can explain this, use the ‘eq’ operator, not the ‘==’ operator, when comparing strings in perl.

Perl programs are so annoying. There are so many ways to do everything that you spend more time trying to decipher the language notation than actually writing code.

Why the hell would you ever say “scalar @x” to get the number of elements in an array and why does “length @x” not return the number of elements in the array. What kind of sadistic bastard came up with this?