db created, added tests -- tentative

backend/db/notes.dao.js

@@ -0,0 +1,54 @@
+import { query } from './index.js';
+
+export const getAllNotes = async () => {
+  const { rows } = await query(
+    'SELECT id, text, x, y, author, color FROM notes ORDER BY id'
+  );
+  return rows;
+};
+
+export const getNoteById = async (id) => {
+  const { rows } = await query(
+    'SELECT id, text, x, y, author, color FROM notes WHERE id = $1',
+    [id]
+  );
+  return rows[0] || null;
+};
+
+export const createNote = async (note) => {
+  const { rows } = await query(
+    `INSERT INTO notes (id, text, x, y, author, color)
+     VALUES ($1, $2, $3, $4, $5, $6)
+     RETURNING id, text, x, y, author, color`,
+    [note.id, note.text, note.x ?? 0, note.y ?? 0, note.author, note.color ?? 'yellow']
+  );
+  return rows[0];
+};
+
+export const createNotes = async (notes) => {
+  const values = [];
+  const placeholders = [];
+
+  notes.forEach((note, i) => {
+    const offset = i * 6;
+    placeholders.push(
+      `($${offset + 1}, $${offset + 2}, $${offset + 3}, $${offset + 4}, $${offset + 5}, $${offset + 6})`
+    );
+    values.push(
+      note.id,
+      note.text,
+      note.x ?? 0,
+      note.y ?? 0,
+      note.author,
+      note.color ?? 'yellow'
+    );
+  });
+
+  const { rows } = await query(
+    `INSERT INTO notes (id, text, x, y, author, color)
+     VALUES ${placeholders.join(', ')}
+     RETURNING id, text, x, y, author, color`,
+    values
+  );
+  return rows;
+};