데이터베이스 추가
실제 데이터를 저장하고 불러옵니다.
데이터베이스 추가은(는) CoddyKit의 무료 Vibe Coding 강의입니다. 이것은 4개 중 3번째 강의입니다. 아래에서 전체 강의를 무료로 읽을 수 있으며, 내장 코드 에디터와 24/7 AI 튜터와 함께 브라우저에서 직접 실습할 수 있습니다. 이 강의는 Vibe Coding 학습 경로의 일부이며, 진행 상황이 웹과 CoddyKit 앱에 동기화됩니다. Vibe Coding 강의에는 총 4개의 강의가 포함되어 있습니다.
이 강의의 일부는 아직 번역되지 않았으며 영어로 표시됩니다.
Make Your Data Permanent
Right now your app stores time entries in memory — restart the server and they're gone. Real apps need a database: a place that stores data permanently and lets you read, add, update and delete it reliably.
In this lesson you'll have AI add a real database to your full-stack app and swap your in-memory array for true storage. The best part: you describe what you want, and AI handles most of the setup.
What a Database Actually Does
Think of a database as a smart, permanent spreadsheet. Data lives in tables (or collections), each row is one record, and each column is a field — exactly like the data model you planned earlier.
You interact with it through CRUD operations: Create, Read, Update, Delete. Almost everything an app does with data is one of those four.
Explain databases to a beginner using my freelancer hours app.
Cover:
- what a table/row/column is, using TimeEntry as the example
- what CRUD means with one example operation each
- how this maps to the data model in my PROJECT.md
No jargon dumps — keep it concrete and short.SQL vs. NoSQL (Pick With AI)
Two broad styles exist. SQL databases (like PostgreSQL) store data in structured tables with relationships — great when your data has clear shape. NoSQL databases (like MongoDB or Firestore) store flexible documents.
For most vibe-coded apps, a hosted SQL database is a solid default. Let AI recommend one and justify it for your project.
For my freelancer hours app (clients and time entries with clear relationships), recommend ONE database.
Compare SQL vs NoSQL in 3 sentences for my case, then pick one. Favor a hosted, beginner-friendly option that works smoothly with Next.js and deploys easily (e.g. a Postgres host like Supabase or Neon). Explain why.Hosted Databases Save You Setup
You could install a database on your computer, but for vibe coding a hosted database is far easier — services like Supabase, Neon or PlanetScale run it in the cloud and give you a connection URL.
You create a project in their dashboard, copy a connection string, and AI wires it into your app. No servers to manage.
Walk me through, step by step, how to create a free Postgres database on Supabase and get my connection string.
Then tell me exactly where to put that connection string in a Next.js project so it stays secret (not in my code, not in my prompts). List the steps as a numbered checklist.Let AI Define Your Schema
A schema is the blueprint of your tables — names, columns, types and relationships. Instead of writing it by hand, hand AI your data model and ask for the schema.
Many stacks use an ORM like Prisma that lets you define the schema in one file, which AI is very good at generating.
Using Prisma with Postgres, write a schema for my freelancer hours app based on this data model:
- Client: id, name
- TimeEntry: id, hours, date, note, belongs to a Client
Give me the schema.prisma file, and the commands to create the tables in my database. Explain the relation line so I understand it.Swap Memory for the Database
Now upgrade the endpoints you built earlier. Where they used an in-memory array, they should now read from and write to the real database.
Tell AI exactly which endpoints to update and which database client to use. Doing this per-endpoint keeps it testable.
Update my /api/entries endpoints to use Prisma instead of the in-memory array.
- POST /api/entries: create a TimeEntry row in the database
- GET /api/entries: return all entries ordered by date, newest first
Keep the same JSON shape the frontend already expects. Show the updated route code and note anything I must run before it works.CRUD in Plain JavaScript
Under the hood, CRUD is just operations on a list of records. Here's a tiny in-memory version of the four operations — the same logic a database does at scale. Run it to watch create, read, update and delete in action.
let entries = [];
let nextId = 1;
function create(data) { const row = { id: nextId++, ...data }; entries.push(row); return row; }
function readAll() { return entries; }
function update(id, changes) { const row = entries.find(e => e.id === id); if (row) Object.assign(row, changes); return row; }
function remove(id) { entries = entries.filter(e => e.id !== id); }
create({ client: "Acme", hours: 3 });
create({ client: "Globex", hours: 2 });
update(1, { hours: 5 });
remove(2);
console.log(readAll());Add Update and Delete Endpoints
So far you can create and read. Real apps also need to edit and remove data — a freelancer fixes a typo in hours or deletes a wrong entry.
Ask AI to add the remaining CRUD endpoints, keeping them consistent with the ones you have.
Add the remaining CRUD endpoints for time entries using Prisma:
- PUT /api/entries/[id]: update an entry's fields
- DELETE /api/entries/[id]: delete an entry
Validate the id, return clear errors if the entry doesn't exist, and match the style of my existing GET/POST routes. Show me how the frontend would call each one.Migrations: Changing the Schema Safely
Your data needs will change — you'll add a column or a new table. A migration is a tracked, repeatable change to your database structure so you can update it without losing existing data.
Tools like Prisma generate migrations for you. Always ask AI to use migrations rather than editing the database by hand, so changes are safe and reversible.
I want to add an 'hourlyRate' field to the Client table without losing existing data.
Update my Prisma schema, then give me the exact migration command to apply this change safely. Explain why using a migration is safer than editing the database directly, and what happens to existing rows.Verify Data Survives a Restart
The whole point of a database is permanence. Test it: add an entry, stop and restart your app, then reload — the entry should still be there.
If data vanishes, you may still be hitting the in-memory array somewhere, or the connection isn't set. Describe the symptom to AI and let it find the leftover code.
I added the database, but after I restart the server my time entries disappear. They should be stored in Postgres.
Help me figure out why. What should I check to confirm the endpoints are actually hitting the database and not a leftover in-memory array? Give me a short diagnostic checklist.Real Data, Real App
Your app now has true persistence: data is created, read, updated and deleted in a real hosted database and survives restarts. You've covered all four CRUD operations and learned to evolve your schema safely with migrations.
One big piece remains for a complete product: knowing who is using the app. Next, we'll add user accounts and login.
Quick Check
Confirm the database fundamentals.
Recap: Adding Real Storage
You gave your app a memory that lasts:
- A database stores data permanently in tables (rows and columns)
- You operate on it with CRUD: Create, Read, Update, Delete
- A hosted database (Supabase, Neon) removes setup pain
- AI generated your schema and swapped in-memory storage for real persistence
- Migrations let you change the schema safely
Next: add user accounts so each freelancer sees only their own data.
자주 묻는 질문
“데이터베이스 추가” 강의는 무료인가요?
네 — “데이터베이스 추가” 전체 내용을 이 웹사이트에서 무료로 읽을 수 있습니다. 인터랙티브하게 실습하려면(내장 코드 에디터와 24/7 AI 튜터), CoddyKit PRO로 업그레이드하면 Vibe Coding 강의 전체를 잠금 해제할 수 있습니다. Vibe Coding 강의에는 총 4개의 강의가 포함되어 있습니다.
“데이터베이스 추가”에서 뭘 배우나요?
실제 데이터를 저장하고 불러옵니다. 브라우저에서 직접 실행하는 실습 코드로 Vibe Coding을(를) 배우며, 24/7 AI 튜터가 강의를 진행하면서 질문에 답변해줍니다.
Vibe Coding을(를) 시작하는 데 경험이 필요한가요?
사전 경험은 필요하지 않습니다. CoddyKit의 Vibe Coding은(는) 초급자부터 고급 학습자까지를 위해 구성되어 있으므로, 여기서 시작하거나 처음부터 시작할 수 있으며 자신의 속도대로 진행할 수 있습니다. 이것은 4개 중 3번째 강의입니다.
“데이터베이스 추가” 강의는 얼마나 걸리나요?
대부분의 CoddyKit 강의는 약 5~10분이 소요됩니다. 각 강의는 간결하고 인터랙티브하여 꾸준한 진행이 가능하며, 웹과 앱에서 중단한 부분부터 바로 시작할 수 있습니다.
이 Vibe Coding 강의에서 코드를 작성하고 실행할 수 있나요?
네. 모든 Vibe Coding 강의에는 내장 코드 에디터가 포함되어 있으므로, 브라우저에서 바로 실제 코드를 작성하고 실행한 후 즉시 AI 피드백을 받을 수 있습니다 — 로컬 설정이 필요 없습니다.