Designing the Data Model
Before building your application, you need to decide what data to store and how to organize it. This is your data model — the blueprint for your database. Getting this right early saves significant rework later.
Thinking in Entities
Start by identifying the "things" your application manages. For a todo app, the main entity is a Todo. A blog might have Posts and Comments. An e-commerce site has Products, Orders, and Users.
Each entity becomes a table in your database. Keep your initial model simple — you can always add more entities later as your application grows.
Defining Fields
Each entity has properties — these become columns in your table. For a Todo, you might have:
- id — unique identifier for each todo
- text — the todo content
- completed — whether it's done (true/false)
- created_at — when it was created
Every table needs a primary key — usually an id field — that uniquely identifies each row. This lets you update or delete specific items.
Choosing Data Types
Each field has a type that determines what values it can hold:
- Text/String — words and sentences
- Integer — whole numbers
- Boolean — true or false
- Timestamp — dates and times
Choosing appropriate types helps the database validate data and optimize storage. A completed field should be boolean, not text storing "yes" or "no".
Relationships Between Entities
When entities connect to each other, you model relationships. If users can have multiple todos, each todo needs a user_id field pointing to its owner. This foreign key creates the connection.
For a simple MVP, you might skip user accounts entirely — just one shared todo list. Add complexity only when needed.
Using AI to Design Your Schema
AI excels at generating database schemas. Describe your application and what data it needs:
"Design a database schema for a simple todo app. Each todo has text content, a completed status, and a creation timestamp. I want to track when todos are completed too. Show me the SQL to create the table."
Review the generated schema. Does it include everything you need? Are the data types appropriate? Ask follow-up questions to refine the design.
Keep It Minimal
For your first version, resist the urge to model everything. A todo app doesn't need categories, priorities, due dates, and tags on day one. Start with the essentials, get it working, then add features incrementally.