Add JMH data access benchmark app

src/main/java/com/benchmark/util/DbUtil.java

@@ -0,0 +1,32 @@
+package com.benchmark.util;
+
+import com.benchmark.model.User;
+
+import java.sql.*;
+
+public class DbUtil {
+
+    public static void createSchema(Connection conn) throws SQLException {
+        try (Statement stmt = conn.createStatement()) {
+            stmt.execute("""
+                CREATE TABLE IF NOT EXISTS users (
+                    id         INTEGER PRIMARY KEY,
+                    name       TEXT    NOT NULL,
+                    email      TEXT    NOT NULL,
+                    age        INTEGER NOT NULL,
+                    created_at INTEGER NOT NULL
+                )
+            """);
+        }
+    }
+
+    public static User mapRow(ResultSet rs) throws SQLException {
+        return new User(
+            rs.getLong("id"),
+            rs.getString("name"),
+            rs.getString("email"),
+            rs.getInt("age"),
+            rs.getLong("created_at")
+        );
+    }
+}