Sunday, April 21, 2013

Sorting with Set::sort() in CakePHP 1.2

Sorting data returned from a database query

You're probably thinking "Err... idiot... just use the ORDER BY functionality in the model!". Yeah, we could do that, but that's not much fun!
Here is my freshly baked People controller, which gracefully passes some data to my view. Nothing special here.

<?php
class PeopleController extends AppController {

    var $name = 'People';
    
    function index() {
        $this->set('people', $this->Person->find('all'));
    }
    
}
?>
 
The $people array is in the standard format we receive from our model, and has a belongsTo association (Occupation).
Array
(
    [0] => Array
        (
            [Person] => Array
                (
                    [id] => 1
                    [occupation_id] => 2
                    [name] => Harry Potter
                    [birth_date] => 1980-07-31
                )

            [Occupation] => Array
                (
                    [id] => 2
                    [name] => Student
                )

        )

    [1] => Array
        (
            [Person] => Array
                (
                    [id] => 2
                    [occupation_id] => 1
                    [name] => Albus Dumbledore
                    [birth_date] => 1881-08-01
                )

            [Occupation] => Array
                (
                    [id] => 1
                    [name] => Headmaster
                )

        )

    [2] => Array
        (
            [Person] => Array
                (
                    [id] => 3
                    [occupation_id] => 3
                    [name] => Severus Snape
                    [birth_date] => 1959-01-09
                )

            [Occupation] => Array
                (
                    [id] => 3
                    [name] => Professor
                )

        )

)

Default order

Instead of dumping the entire contents of the $people array after each Set::sort() call, I will present the data in a pretty table.
Person.id Person.name Person.birth_date Occupation.id Occupation.name
1 Harry Potter 1980-07-31 2 Student
2 Albus Dumbledore 1881-08-01 1 Headmaster
3 Severus Snape 1959-01-09 3 Professor

Person.birth_date DESC

Set::sort() currently takes 3 arguments - the array to sort, the array value to sort on, and the sort order. As with the other Set methods, we specify the value to sort on using a key path. This makes it super easy to deal with complex arrays.

$people = Set::sort($people, '{n}.Person.birth_date', 'desc');
 

Person.id Person.name Person.birth_date Occupation.id Occupation.name
1 Harry Potter 1980-07-31 2 Student
3 Severus Snape 1959-01-09 3 Professor
2 Albus Dumbledore 1881-08-01 1 Headmaster

Occupation.name ASC

It's just as simple sorting on a value of an associated model, in this case the person's occupation. Unfortunately the sort method doesn't current have a default sort order, so we need to specify this. We can also use the PHP constants, SORT_ASC and SORT_DESC.

$people = Set::sort($people, '{n}.Occupation.name', SORT_ASC);
 

Person.id Person.name Person.birth_date Occupation.id Occupation.name
2 Albus Dumbledore 1881-08-01 1 Headmaster
3 Severus Snape 1959-01-09 3 Professor
1 Harry Potter 1980-07-31 2 Student

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