database

# Database

Add official Railway database services. These are maintained templates with pre-configured volumes, networking, and connection variables.

For non-database templates, see the `templates` skill.

## When to Use

- User asks to "add a database", "add Postgres", "add Redis", etc.
- User needs a database for their application
- User asks about connecting to a database
- User says "add postgres and connect to my server"
- User says "wire up the database"

## Decision Flow

**ALWAYS check for existing databases FIRST before creating.**

```
User mentions database
        │
  Check existing DBs first
  (query env config for source.image)
        │
   ┌────┴────┐
 Exists    Doesn't exist
    │           │
    │      Create database
    │      (CLI or API)
    │           │
    │      Wait for deployment
    │           │
    └─────┬─────┘
          │
    User wants to
    connect service?
          │
    ┌─────┴─────┐
   Yes         No
    │           │
Wire vars    Done +
via env     suggest wiring
skill
```

## Check for Existing Databases

Before creating a database, check if one already exists.

For full environment config structure, see [environment-config.md](references/environment-config.md).

```bash
railway status --json
```

Then query environment config and check `source.image` for each service:

```graphql
query environmentConfig($environmentId: String!) {
  environment(id: $environmentId) {
    config(decryptVariables: false)
  }
}
```

The `config.services` object contains each service's configuration. Check `source.image` for:

- `ghcr.io/railway/postgres*` or `postgres:*` → Postgres
- `ghcr.io/railway/redis*` or `redis:*` → Redis
- `ghcr.io/railway/mysql*` or `mysql:*` → MySQL
- `ghcr.io/railway/mongo*` or `mongo:*` → MongoDB

## Available Databases

| Database | Template Code |
|----------|---------------|
| PostgreSQL | `postgres` |
| Redis | `redis` |
| MySQL | `mysql` |
| MongoDB | `mongodb` |

## Prerequisites

Get project context:
```bash
r