Database Operations Skill

This skill provides guidance for common MongoDB database operations in the To-Do List WebApp project.

Prerequisites

•Docker running with MongoDB container
•MongoDB container name: todolist-mongodb (or check with docker ps)

Connecting to MongoDB

Using Docker Exec

Connect to MongoDB shell inside the container:

bash

# Find container name
docker ps | grep mongo

# Connect to MongoDB shell
docker exec -it todolist-webapp-mongodb-1 mongosh todolist

Using MongoDB Compass (GUI)

•Install MongoDB Compass: https://www.mongodb.com/products/compass
•Connect with URI: mongodb://localhost:27017/todolist

Using mongo Shell Locally

If you have MongoDB installed locally:

bash

mongosh "mongodb://localhost:27017/todolist"

Viewing Data

List All Collections

javascript

// In mongosh
show collections

View Documents

javascript

// View all users
db.users.find().pretty()

// View all todos
db.todos.find().pretty()

// View all projects
db.projects.find().pretty()

// Count documents
db.todos.countDocuments()
db.users.countDocuments()

Query Examples

javascript

// Find todos by user
db.todos.find({ userId: 'USER_ID' })

// Find completed todos
db.todos.find({ completed: true })

// Find todos with specific priority
db.todos.find({ priority: 'high' })

// Find recent todos
db.todos.find().sort({ createdAt: -1 }).limit(10)

Backup Database

Using Docker and mongodump

Run the backup script:

bash

node .agent/skills/db-operations/scripts/backup-db.js

Or manually:

bash

# Create backup directory
mkdir -p db/backups

# Backup using mongodump
docker exec todolist-webapp-mongodb-1 mongodump --db todolist --archive=/data/db/backup.archive

# Copy backup from container to host
docker cp todolist-webapp-mongodb-1:/data/db/backup.archive ./db/backups/backup-$(date +%Y%m%d-%H%M%S).archive

Scheduled Backups

For regular backups, create a cron job or scheduled task:

bash

# Linux/Mac: Add to crontab
# Backup every day at 2 AM
0 2 * * * cd /path/to/project && node .agent/skills/db-operations/scripts/backup-db.js

Restore Database

From Backup Archive

Run the restore script:

bash

node .agent/skills/db-operations/scripts/restore-db.js <backup-file>

Or manually:

bash

# Copy backup to container
docker cp ./db/backups/backup-YYYYMMDD-HHMMSS.archive todolist-webapp-mongodb-1:/data/db/restore.archive

# Restore using mongorestore
docker exec todolist-webapp-mongodb-1 mongorestore --db todolist --archive=/data/db/restore.archive --drop

Note: The --drop flag will drop existing collections before restoring.

Database Maintenance

Clear All Data (Development Only)

⚠️ WARNING: This will delete all data!

javascript

// In mongosh
db.todos.deleteMany({})
db.users.deleteMany({})
db.projects.deleteMany({})
db.notificationsubscriptions.deleteMany({})

Reset Database

To completely reset the database:

bash

# Stop containers
docker-compose down

# Remove volumes
docker volume rm todolist-webapp_mongodb-data

# Restart
docker-compose up -d

Optimize Database

javascript

// In mongosh
// Rebuild indexes
db.todos.reIndex()
db.users.reIndex()

// Compact collection
db.runCommand({ compact: 'todos' })

// Get database stats
db.stats()

Index Management

View Indexes

javascript

// In mongosh
db.todos.getIndexes()
db.users.getIndexes()

Create Indexes

javascript

// Create index on userId for faster queries
db.todos.createIndex({ userId: 1 })

// Create compound index
db.todos.createIndex({ userId: 1, completed: 1 })

// Create text index for search
db.todos.createIndex({ title: 'text', description: 'text' })

Drop Indexes

javascript

// Drop specific index
db.todos.dropIndex('userId_1')

// Drop all indexes except _id
db.todos.dropIndexes()

Data Migration

Export Data to JSON

bash

# Export entire database
docker exec todolist-webapp-mongodb-1 mongoexport --db todolist --collection todos --out /data/db/todos.json

# Copy to host
docker cp todolist-webapp-mongodb-1:/data/db/todos.json ./db/exports/todos.json

Import Data from JSON

bash

# Copy to container
docker cp ./db/exports/todos.json todolist-webapp-mongodb-1:/data/db/todos.json

# Import
docker exec todolist-webapp-mongodb-1 mongoimport --db todolist --collection todos --file /data/db/todos.json

Monitoring

Database Size

javascript

// In mongosh
db.stats(1024*1024) // Size in MB

Connection Status

bash

# Check MongoDB container logs
docker logs todolist-webapp-mongodb-1

# Follow logs in real-time
docker logs -f todolist-webapp-mongodb-1

Active Connections

javascript

// In mongosh
db.serverStatus().connections

Troubleshooting

Connection Refused

•
Check if MongoDB container is running:
bash
```
docker ps | grep mongo
```
•
Check container logs:
bash
```
docker logs todolist-webapp-mongodb-1
```
•
Restart container:
bash
```
docker-compose restart mongodb
```

Storage Full

•
Check disk usage:
bash
```
docker system df
```
•
Clean up unused volumes:
bash
```
docker volume prune
```
•
Remove old backups:
bash
```
rm -rf db/backups/old-backups
```

Slow Queries

•

Enable profiling:

javascript

db.setProfilingLevel(1, { slowms: 100 })

•

View slow queries:

javascript

db.system.profile.find().sort({ ts: -1 }).limit(5)

•
Add appropriate indexes

Best Practices

•Regular Backups: Schedule daily backups to prevent data loss
•Index Optimization: Create indexes for frequently queried fields
•Monitor Size: Keep an eye on database size and plan for scaling
•Test Restores: Periodically test backup restoration process
•Separate Environments: Use different databases for dev, test, and production
•Access Control: In production, enable authentication and use strong passwords

Useful Commands

bash

# Database status
docker exec todolist-webapp-mongodb-1 mongosh --eval "db.serverStatus()"

# List all databases
docker exec todolist-webapp-mongodb-1 mongosh --eval "show dbs"

# Database size
docker exec todolist-webapp-mongodb-1 mongosh todolist --eval "db.stats(1024*1024)"

# Collection stats
docker exec todolist-webapp-mongodb-1 mongosh todolist --eval "db.todos.stats()"