REGEX: grouping of alternative patterns

Hey list,

I'm having problems with grouped alternative patterns.
The regex I would like to use, is the following:

/\s*(`?.+`?)\s*int\s*(\(([0-9]+)\))?\s*(unsigned)?\s*(((auto_increment)?\s*(primary\s*key)?)|((not\s*null)?\s*(default\s*(`.*`|[0-9]*)?)?))\s*/i

It matches this statement:

`id` INT(11) UNSIGNED AUTO_INCREMENT PRIMARY KEY

But not this:

`test4` INT(11) UNSIGNED NOT NULL DEFAULT 5

However, if I switch the alternatives, the first statement doesn't match, but the second does.
FYI: In both cases, the column name and data type are matched, as expected.
It appears to be doing lazy evaluation on the pattern, even though every resource I can find states that every alternative is tried in turn until a match is found.

Any ideas on how this can be resolved would be greatly appreciated.

Here is some code:

<?php
$pattern1 = '/\s*(`?.+`?)\s*int\s*(\(([0-9]+)\))?\s*(unsigned)?\s*(((auto_increment)?\s*(primary\s*key)?)|((not\s*null)?\s*(default\s*(`.*`|[0-9]*)?)?))\s*/i';
$pattern2 = '/\s*(`?.+`?)\s*int\s*(\(([0-9]+)\))?\s*(unsigned)?\s*(((not\s*null)?\s*(default\s*(`.*`|[0-9]*)?)?)|((auto_increment)?\s*(primary\s*key)?))\s*/i';
$column1 = '`id` INT(11) UNSIGNED AUTO_INCREMENT PRIMARY KEY';
$column2 = '`test4` INT(11) UNSIGNED NOT NULL DEFAULT 5';
$matches = array();

preg_match($pattern1, $column1, $matches); print_r($matches); // match
preg_match($pattern1, $column2, $matches); print_r($matches); // doesn't match

preg_match($pattern2, $column1, $matches); print_r($matches); // doesn't match
preg_match($pattern2, $column2, $matches); print_r($matches); // match
?>


Greetz,

Stijn
.