php 属性 PHP 实体-属性-值 (EAV)模式

实体-属性-值 (EAV) 模式以使用 PHP 实现 EAV 模型。

目的

Entity-attribute-value (EAV) 模型是一种描述实体的数据模型，其中可用于描述它们的属性（属性、参数）的数量可能很大，但实际应用于给定实体的数量是比较适中。

UML 图

代码

Entity.php

<?php

declare(strict_types=1);

namespace DesignPatternsMoreEAV;

use SplObjectStorage;

class Entity implements Stringable
{
    
    private $values;

    
    public function __construct(private string $name, $values)
    {
        $this->values = new SplObjectStorage();

        foreach ($values as $value) {
            $this->values->attach($value);
        }
    }

    public function __toString(): string
    {
        $text = [$this->name];

        foreach ($this->values as $value) {
            $text[] = (string) $value;
        }

        return join(", ", $text);
    }
}

Attribute.php

<?php

declare(strict_types=1);

namespace DesignPatternsMoreEAV;

use SplObjectStorage;

class Attribute implements Stringable
{
    private SplObjectStorage $values;

    public function __construct(private string $name)
    {
        $this->values = new SplObjectStorage();
    }

    public function addValue(Value $value)
    {
        $this->values->attach($value);
    }

    public function getValues(): SplObjectStorage
    {
        return $this->values;
    }

    public function __toString(): string
    {
        return $this->name;
    }
}

Value.php

<?php

declare(strict_types=1);

namespace DesignPatternsMoreEAV;

class Value implements Stringable
{
    public function __construct(private Attribute $attribute, private string $name)
    {
        $attribute->addValue($this);
    }

    public function __toString(): string
    {
        return sprintf("%s: %s", (string) $this->attribute, $this->name);
    }
}

测试

Tests/EAVTest.php

<?php

declare(strict_types=1);

namespace DesignPatternsMoreEAVTests;

use DesignPatternsMoreEAVAttribute;
use DesignPatternsMoreEAVEntity;
use DesignPatternsMoreEAVValue;
use PHPUnitFrameworkTestCase;

class EAVTest extends TestCase
{
    public function testCanAddAttributeToEntity()
    {
        $colorAttribute = new Attribute("color");
        $colorSilver = new Value($colorAttribute, "silver");
        $colorBlack = new Value($colorAttribute, "black");

        $memoryAttribute = new Attribute("memory");
        $memory8Gb = new Value($memoryAttribute, "8GB");

        $entity = new Entity("MacBook Pro", [$colorSilver, $colorBlack, $memory8Gb]);

        $this->assertEquals("MacBook Pro, color: silver, color: black, memory: 8GB", (string) $entity);
    }
}