回答です

answer/Ex03.php

@@ -0,0 +1,34 @@
+<?php
+// Ex03_answer.php
+
+$dsn = "mysql:host=localhost;dbname=employee_db;charset=utf8";
+$username = "rezouser";
+$password = "Rezo_0000";
+
+try {
+    $pdo = new PDO($dsn, $username, $password);
+    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
+
+    $sql = "INSERT INTO employees (name, dep_id, project_id, salary)
+            VALUES (:name, :dep_id, :project_id, :salary)";
+    $stmt = $pdo->prepare($sql);
+
+    // サンプルデータの設定
+    $name = "山田一郎";
+    $dept_id = 1;
+    $project_id = 2;
+    $salary = 250000;
+
+    $stmt->bindParam(':name', $name, PDO::PARAM_STR);
+    $stmt->bindParam(':dep_id', $dept_id, PDO::PARAM_INT);
+    $stmt->bindParam(':project_id', $project_id, PDO::PARAM_INT);
+    $stmt->bindParam(':salary', $salary, PDO::PARAM_INT);
+
+    $stmt->execute();
+
+    echo "レコードを挿入しました";
+} catch (PDOException $e) {
+    echo "エラー: " . $e->getMessage();
+} finally {
+    $pdo = null;
+}