Data Model Template for Apps

TL;DR: A clear data model prevents AI from inventing entities and relationships. Design it right, document it, and AI follows.

Table of Contents

1. Data Model Basics
2. Common Patterns
3. Design Process
4. Example Model
5. Template

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Data Model Basics

What to Define

Element	Description
Entities	Things you store (users, projects, tasks)
Attributes	Properties of entities (name, email, status)
Relationships	How entities connect (user owns projects)
Constraints	Rules (unique emails, required names)

For AI Tools

AI needs to know:

• What tables exist
• What columns are in each table
• How tables relate
• What constraints apply

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Common Patterns

Pattern: User Ownership

erDiagram
    users ||--o{ projects : owns
    projects {
        uuid id PK
        uuid user_id FK
        text name
    }

Pattern: Soft Delete

deleted_at TIMESTAMPTZ  -- NULL = not deleted, timestamp = deleted

Pattern: Timestamps

created_at TIMESTAMPTZ DEFAULT now()
updated_at TIMESTAMPTZ DEFAULT now()

Pattern: Status Enum

status TEXT CHECK (status IN ('draft', 'active', 'archived'))

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Design Process

1. List entities — What things do you store?
2. Define attributes — What properties does each have?
3. Map relationships — How do entities connect?
4. Add constraints — What rules must data follow?
5. Document — Write it in schema.md

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Example Model

Task Manager Data Model

erDiagram
    users ||--o{ projects : owns
    projects ||--o{ tasks : contains

    users {
        uuid id PK
        text email UK
        text name
        text role
    }

    projects {
        uuid id PK
        uuid user_id FK
        text name
        text status
    }

    tasks {
        uuid id PK
        uuid project_id FK
        text title
        boolean completed
    }

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Template

→ Download Database Schema Template

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Related

• Schema Template
• Architecture Doc
• API Spec Template

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Model your data, ground your AI. Generate →

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Last updated: January 2026