增删改查 CRUD
INSERT/UPDATE/DELETE/SELECT、命名占位符、lastInsertId
增删改查 CRUD
CRUD 是 Web 开发的核心操作。PDO 让这些操作既安全又简洁。
学完本章你将： 掌握 INSERT/UPDATE/DELETE/SELECT、命名占位符、lastInsertId。
SELECT 查询
php
<?php
// 查所有
$stmt = $pdo->query("SELECT * FROM users ORDER BY id DESC");
$users = $stmt->fetchAll();
// 条件查询
$stmt = $pdo->prepare("SELECT * FROM users WHERE age > :age");
$stmt->execute(["age" => 18]);
$adults = $stmt->fetchAll();
// 查单个
$stmt = $pdo->prepare("SELECT * FROM users WHERE id = :id");
$stmt->execute(["id" => 1]);
$user = $stmt->fetch();INSERT 插入
php
<?php
$stmt = $pdo->prepare(
"INSERT INTO users (name, email, age) VALUES (:name, :email, :age)"
);
$stmt->execute([
"name" => "小明",
"email" => "xm@example.com",
"age" => 25,
]);
$newId = $pdo->lastInsertId();
echo "新用户 ID：$newId";UPDATE / DELETE
php
<?php
// 更新
$stmt = $pdo->prepare(
"UPDATE users SET age = :age WHERE id = :id"
);
$stmt->execute(["age" => 26, "id" => 1]);
echo "影响行数：" . $stmt->rowCount();
// 删除
$stmt = $pdo->prepare("DELETE FROM users WHERE id = :id");
$stmt->execute(["id" => 1]);
// 软删除（推荐）
// UPDATE users SET deleted_at = NOW() WHERE id = :id