PHP Query

PHP-Query contains a single, instantiable, class, which provides a PHP ORM like API for plain and straightforward query generation.
Queries are not executed by the class or ORM, but rather return the SQL statement that ought to be run against a database resource.
While it is modelled after the ActiveRecord pattern, it follows plain language that I felt would make code easier to read and maintain.

API Samples

// select a username's details
$query = new Query();
$query->select('*');
$query->from('users');
$query->where('username', 'onassar');
$parsed = $query->parse();

// update a user record
$query = new Query();
$query->update('users');
$query->set('fname', 'Oliver');
$query->where('username', 'onassar');
$parsed = $query->parse();

// insert a user record
$query = new Query();
$query->insert(array(
    'fname' => 'Oliver',
    'lname' => 'Nassar',
    'username' => 'onassar'
));
$query->into('users');
$parsed = $query->parse();

Performance

Worth mentioning is that this approach to database-access isn't ideal for speed and memory. You're adding an extra, "unrequired", step for your application.

Any potential speed or memory hits that you may take, however, could (and should) be circumvented by using a proper caching engine, class (see PHP-MemcachedCache and/or PHP-APCCache) and flow.

Update

Regarding the section above, I've stumbled upon some information suggesting that during the filter stage of generating a query, the performance will be effected if a varchar column has it's value compared without apostrophes. Presumably, the converse is true.

As an example, U.username = 12345 should be written as U.username = '12345'.

The Query class presumes that all columns are varchars, and thus wraps the values in apostrophes. The only exception to this is when a third parameter is pased to the where method.

$query->where('user_id', 1) will be rendered as WHERE user_id = '1' vs the proper WHERE user_id = '1'. Passing in that third parameter forces the apostrophes to be left off the value definition.

Keep this in mind if you're concerned about the performance of oftenly executed queries, especially if they're part of any indices.