---
id: php-oop-static-methods
title: "PHP OOP Static Methods"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["static keyword", "parent::", "PHP 정적 메서드"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.9
created_at: 2026-07-04
updated_at: 2026-07-04
review_reason: ""
merge_history: []
tags: ["php", "programming", "w3schools", "oop", "static"]
raw_sources: ["https://www.w3schools.com/php/php_oop_static_methods.asp"]
applied_in: []
github_commit: ""
---

# [[PHP OOP Static Methods]]

## 🎯 한 줄 통찰 (One-line insight)
Calling a static method from a CHILD class requires the `parent::` keyword instead of the class name, even though the static method literally belongs to a specific class — this differs from calling a static method from an unrelated class (which uses the explicit class name like `A::welcome()`), showing `parent::` is reserved specifically for the inheritance relationship. [S1]

## 🧠 핵심 개념 (Core concepts)
- **`static` keyword** — creates a method callable WITHOUT instantiating the class first. [S1]
- **Access via `ClassName::method()`** — the standard way to call a static method from outside. [S1]
- **Access via `self::method()`** — used to call a static method from a non-static method WITHIN the same class (e.g., inside a constructor). [S1]
- **Cross-class static calls** — a static method must be `public` to be called from another class's method. [S1]
- **Access via `parent::method()`** — used specifically when a child class wants to call a static method defined in its parent. [S1]

## 📖 세부 내용 (Details)
- Direct static call: `class greeting { public static function welcome() { echo "Hello World!"; } } greeting::welcome();`. [S1]
- Static call with arguments: `class calc { public static function sum($x, $y) { return $x * $y; } } $res = calc::sum(6, 4);`. [S1]
- Static called via self from constructor: `class greeting { public static function welcome() {...} public function __construct() { self::welcome(); } } new greeting();`. [S1]
- Static called from another class: `class A { public static function welcome() {...} } class B { public function message() { A::welcome(); } }`. [S1]
- Static called via parent:: from a child class: `class domain { protected static function getWebsiteName() { return "W3Schools.com"; } } class domainW3 extends domain { public $websiteName; public function __construct() { $this->websiteName = parent::getWebsiteName(); } }`. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- **상속 관계에서의 특수 키워드**: 자식 클래스에서 부모의 정적 메서드를 호출할 때는 클래스 이름이 아니라 parent:: 키워드를 사용해야 한다는 점이 강조됨. [S1]

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — 부모 클래스의 protected static 메서드를 자식 클래스 생성자에서 parent::로 호출하는 것이 실전 활용의 대표 사례다. [S1]

## 💻 코드 패턴 (Code patterns)
Calling a parent's static method from a child class (PHP):
```php
class domain {
    protected static function getWebsiteName() {
        return "W3Schools.com";
    }
}
class domainW3 extends domain {
    public $websiteName;
    public function __construct() {
        $this->websiteName = parent::getWebsiteName();
    }
}
```

## ✅ 검증 상태 및 신뢰도
- **상태:** draft
- **검증 단계:** conceptual
- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
- **신뢰 점수:** 0.90
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[PHP Tutorial]]
- **관련 개념:** [[PHP OOP Traits]], [[PHP OOP Static Properties]]
- **참조 맥락:** 인스턴스 없이 호출 가능한 메서드 — 정적 속성(Static Properties) 챕터로 직접 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — PHP OOP - Static Methods — https://www.w3schools.com/php/php_oop_static_methods.asp

## 📝 변경 이력 (Change history)
- 2026-07-04: Initial draft synthesized from the W3Schools "PHP OOP Static Methods" page (Astra wiki-curation, P-Reinforce v3.1 format).