# Flask Data Persistence

> Professional database management with SQLAlchemy and Flask-Migrate.

- Skill: `jcorpac/flask-data-persistence` (Agent Skill)
- Install (CLI): `npx skillmds@latest add jcorpac/flask-data-persistence`
- Raw SKILL.md: https://api.skillmd.com/api/skills/jcorpac/flask-data-persistence/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: jcorpac (https://skillmd.com/u/jcorpac)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/jcorpac/flask-data-persistence

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# Flask Data Persistence

Managing state is at the heart of any web app. This skill focuses on the SQLAlchemy ORM.

## Models & relationships
- **Declarative Base**: Defining tables as Python classes.
- **Relationships**: Using `db.relationship` for One-to-Many and Many-to-Many mappings.

## Migrations (Flask-Migrate)
Never manually edit your database schema. Use migrations.
1. **init**: `flask db init`
2. **generate**: `flask db migrate -m "Added user bio"`
3. **apply**: `flask db upgrade`

## Performance
- **Lazy Loading**: Understanding `select`, `joined`, and `subquery` loading strategies to avoid N+1 problems.
- **Pagination**: Use `paginate()` for manageable data display.

## Best Practices
- **Transactions**: Ensure atomic updates within a single request context.
- **Sensitive Data**: Hash passwords before storing using `Werkzeug` or `Passlib`.