---

name: postgresql description: PostgreSQL database patterns for Neon serverless database. Use when configuring database connections, writing queries, or optimizing PostgreSQL for the Todo backend. allowed-tools: Read, Edit, Write, Glob, Grep, Bash

PostgreSQL Skill

Quick Reference

PostgreSQL is the database used with Neon Serverless for the Todo app.

Neon Connection

CopyDATABASE_URL = os.getenv(
    "DATABASE_URL",
    "postgresql://user:pass@ep-xxx.us-east-1.aws.neon.tech/neon?sslmode=require"
)

# SSL is required for Neon
engine = create_engine(
    DATABASE_URL,
    pool_pre_ping=True,  # Verify connection before use
)

Common Queries

Copy-- List tasks for user
SELECT * FROM tasks WHERE user_id = 'user_123' ORDER BY created_at DESC;

-- Count tasks by status
SELECT completed, COUNT(*) FROM tasks WHERE user_id = 'user_123' GROUP BY completed;

-- Search tasks
SELECT * FROM tasks WHERE title ILIKE '%groceries%';

-- Update task
UPDATE tasks SET completed = true, updated_at = NOW() WHERE id = 1 AND user_id = 'user_123';

-- Delete task
DELETE FROM tasks WHERE id = 1 AND user_id = 'user_123';

Indexes for Performance

Copy-- User task lookup
CREATE INDEX IF NOT EXISTS idx_tasks_user_id ON tasks(user_id);

-- Status filtering
CREATE INDEX IF NOT EXISTS idx_tasks_user_completed ON tasks(user_id, completed);

-- Date sorting
CREATE INDEX IF NOT EXISTS idx_tasks_user_created ON tasks(user_id, created_at DESC);

For Detailed Reference

See REFERENCE.md for:

• Advanced queries
• Performance tuning
• Neon-specific considerations
• Backup and recovery