ar-position

This extension provides support for ActiveRecord custom records order setup.

For license information check the LICENSE-file.

Installation

The preferred way to install this extension is through composer.

Either run

php composer.phar require --prefer-dist yii2tech/ar-position

or add

"yii2tech/ar-position": "*"

to the require section of your composer.json.

Usage

This extension provides support for custom records order setup via column-based position index.

This extension provides \yii2tech\ar\position\PositionBehavior ActiveRecord behavior for such solution
support in Yii2. You may attach it to your model class in the following way:

<?php

use yii\db\ActiveRecord;
use yii2tech\ar\position\PositionBehavior;

class Item extends ActiveRecord
{
    public function behaviors()
    {
        return [
            'positionBehavior' => [
                'class' => PositionBehavior::className(),
                'positionAttribute' => 'position',
            ],
        ];
    }
}

Behavior uses the specific integer field of the database entity to set up position index.
Due to this the database entity, which the model refers to, must contain field positionAttribute.

In order to display custom list in correct order you should sort it by positionAttribute in ascending mode:

<?php

$records = Item::find()->orderBy(['position' => SORT_ASC])->all();
foreach ($records as $record) {
    echo $record->position . ', ';
}
// outputs: 1, 2, 3, 4, 5,...

Position saving

Being attached, behavior automatically fills up positionAttribute value for the new record, placing it to the end
of the list:

<?php

echo Item::find()->count(); // outputs: 4

$item = new Item();
$item->save();

echo $item->position; // outputs: 5

However, you may setup position for the new record explicitly:

<?php

echo Item::find()->count(); // outputs: 4

$item = new Item();
$item->position = 2; // enforce position '2'
$item->save();

echo $item->position; // outputs: 2 !!!

Position switching

Existing record can be moved to another position using following methods:

• movePrev() - moves record by one position towards the start of the list.
• moveNext() - moves record by one position towards the end of the list.
• moveFirst() - moves record to the start of the list.
• moveLast() - moves record to the end of the list.
• moveToPosition() - moves owner record to the specific position.

You may as well change record position through the attribute, provided to positionAttribute directly:

<?php

$item = Item::find()->andWhere(['position' => 3])->one();
$item->position = 5; // switch position to '5'
$item->save();

Position in group

Sometimes single database entity contains several listings, which require custom ordering, separated logically
by grouping attributes. For example: FAQ questions may be grouped by categories, while inside single category
questions should be ordered manually. For this case \yii2tech\ar\position\PositionBehavior::$groupAttributes
can be used:

<?php

use yii\db\ActiveRecord;
use yii2tech\ar\position\PositionBehavior;

class FaqQuestion extends ActiveRecord
{
    public function behaviors()
    {
        return [
            'positionBehavior' => [
                'class' => PositionBehavior::className(),
                'positionAttribute' => 'position',
                'groupAttributes' => [
                    'categoryId' // multiple lists varying by 'categoryId'
                ],
            ],
        ];
    }
}

In this case behavior will use owner values of groupAttributes as additional condition for position
calculation and changing:

<?php

echo FaqQuestion::find()->andWhere(['categoryId' => 1])->count(); // outputs: '4'
echo FaqQuestion::find()->andWhere(['categoryId' => 2])->count(); // outputs: '7'

$record = new FaqQuestion();
$record->categoryId = 1;
$record->save();
echo $record->position; // outputs: '5'

$record = new FaqQuestion();
$record->categoryId = 2;
$record->save();
echo $record->position; // outputs: '8'

List navigation

Records with custom position order applied make a chained list, which you may navigate if necessary.
You may use \yii2tech\ar\position\PositionBehavior::getIsFirst() and \yii2tech\ar\position\PositionBehavior::getIsLast()
methods to determine if particular record is the first or last one in the list. For example:

<?php

echo Item::find()->count(); // outputs: 10

$firstItem = Item::find()->andWhere(['position' => 1])->one();
echo $firstItem->getIsFirst(); // outputs: true
echo $firstItem->getIsLast(); // outputs: false

$lastItem = Item::find()->andWhere(['position' => 10])->one();
echo $lastItem->getIsFirst(); // outputs: false
echo $lastItem->getIsLast(); // outputs: true

Having a particular record instance, you can always find record, which is located at next or previous position to it,
using \yii2tech\ar\position\PositionBehavior::getNext() or \yii2tech\ar\position\PositionBehavior::getPrev() method.
For example:

<?php

$item = Item::find()->andWhere(['position' => 5])->one();

$nextItem = $item->findNext();
echo $nextItem->position; // outputs: 6

$prevItem = $item->findPrev();
echo $prevItem->position; // outputs: 4

You may as well get the first and the last records in the list. For example:

<?php

echo Item::find()->count(); // outputs: 10
$item = Item::find()->andWhere(['position' => 5])->one();

$firstItem = $item->findFirst();
echo $firstItem->position; // outputs: 1

$lastItem = $item->findLast();
echo $lastItem->position; // outputs: 10