# Podcastrr Migration Guide

## Resolving Common Database Errors

### "no such column: podcasts.tags" Error

If you encounter the following error when accessing podcast pages:

```
sqlite3.OperationalError: no such column: podcasts.tags
```

This means that your database schema is out of date and missing the `tags` column in the `podcasts` table. This can happen if you've updated the codebase but haven't run the necessary database migrations.

### "no such table: episodes" Error

If you encounter the following error when starting the application:

```
Error running migration: no such table: episodes
```

This means that the migration script is trying to modify the episodes table before it has been created. This issue has been fixed in the latest version of the application, which ensures that tables are created before migrations are run.

## How to Fix the Issue

### Option 1: Run the Migration Script

The simplest way to fix this issue is to run the provided migration script:

```
python run_migrations.py
```

This script will run all necessary migrations, including adding the `tags` column to the `podcasts` table.

### Option 2: Reinitialize the Database

If you're still having issues, you can reinitialize the database:

```
python init_db.py
```

This will create all tables and run all migrations. Note that this will preserve your existing data.

## Understanding Migrations in Podcastrr

Podcastrr uses a simple migration system to update the database schema when new features are added. Migrations are stored in the `migrations` directory and are automatically run when:

1. The application starts (via `application.py`)
2. The database is initialized (via `init_db.py`)
3. The migration script is run (via `run_migrations.py`)

## Adding New Migrations

If you need to add a new migration:

1. Create a new Python file in the `migrations` directory (e.g., `add_new_feature.py`)
2. Implement a `run_migration()` function that makes the necessary database changes
3. The migration will be automatically discovered and run by the application

Example migration structure:

```python
"""
Migration script to add a new feature.
"""
import sqlite3
from flask import current_app

def run_migration():
    """
    Run the migration to add the new feature.
    """
    # Get the database path
    db_path = current_app.config['SQLALCHEMY_DATABASE_URI'].replace('sqlite:///', '')

    # Connect to the database
    conn = sqlite3.connect(db_path)
    cursor = conn.cursor()

    # Make database changes
    # ...

    # Commit and close
    conn.commit()
    conn.close()

    print("Migration completed successfully!")
    return True
```

## Troubleshooting

If you're still experiencing issues after running the migrations:

1. Check the application logs for detailed error messages
2. Verify that the database file exists and is accessible
3. Ensure that the migration scripts are in the correct location
4. Try restarting the application after running the migrations