> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/feathersjs/feathers/llms.txt
> Use this file to discover all available pages before exploring further.

# Connection command

> Add a new database connection to your Feathers application

The `feathers generate connection` command adds a new database connection to your application. This command is used to set up additional database connections beyond the initial one configured during app generation.

## Usage

```bash theme={null}
feathers generate connection
```

**Alias:** `feathers g connection`

## Interactive Prompts

When you run this command, you'll be prompted for:

### Database Type

<ParamField path="database" type="string" required>
  The type of database to connect to

  **Choices:**

  * `sqlite` - SQLite (file-based, no server required)
  * `mongodb` - MongoDB
  * `postgresql` - PostgreSQL
  * `mysql` - MySQL/MariaDB
  * `mssql` - Microsoft SQL Server
  * `other` - Other database via custom connection
</ParamField>

### Connection String

<ParamField path="connectionString" type="string" required>
  The connection string for the database

  **Default values by database type:**

  * MongoDB: `mongodb://127.0.0.1:27017/{name}`
  * PostgreSQL: `postgres://postgres:@localhost:5432/{name}`
  * MySQL: `mysql://root:@localhost:3306/{name}`
  * SQLite: `{name}.sqlite`
  * MSSQL: `mssql://root:password@localhost:1433/{name}`
</ParamField>

### Connection Name

<ParamField path="name" type="string">
  Optional name for the connection (used in configuration)

  If not provided, defaults to the database type (e.g., "mongodb", "postgres")
</ParamField>

## What Gets Generated

Running this command will:

<Steps>
  <Step title="Install database adapter">
    Installs the appropriate Feathers database adapter package:

    * `@feathersjs/knex` for SQL databases (PostgreSQL, MySQL, SQLite, MSSQL)
    * `@feathersjs/mongodb` for MongoDB
  </Step>

  <Step title="Install database driver">
    Installs the database-specific driver:

    * `pg` for PostgreSQL
    * `mysql2` for MySQL
    * `better-sqlite3` for SQLite
    * `tedious` for MSSQL
    * `mongodb` for MongoDB
  </Step>

  <Step title="Update configuration">
    Adds the connection string to your configuration files:

    * `config/default.json` - Default configuration
    * `config/production.json` - Production overrides
  </Step>

  <Step title="Create database client">
    Creates a new client file at `src/{name}.ts` that initializes the database connection
  </Step>

  <Step title="Register in application">
    Updates `src/app.ts` to configure and use the database connection
  </Step>
</Steps>

## Example: Adding PostgreSQL

```bash theme={null}
$ feathers generate connection
? Which database are you connecting to? PostgreSQL
? Enter the database connection string: postgres://user:pass@localhost:5432/mydb
? Enter a name for this connection: (postgres) 
```

**Generated files:**

```typescript src/postgres.ts theme={null}
import knex from 'knex'
import type { Application } from './declarations'

export const postgres = (app: Application) => {
  const db = knex({
    client: 'pg',
    connection: app.get('postgres')
  })

  app.set('postgresClient', db)
}
```

**Updated configuration:**

```json config/default.json theme={null}
{
  "postgres": "postgres://user:pass@localhost:5432/mydb"
}
```

## Multiple Connections

You can run this command multiple times to add connections to different databases. Each connection will have its own configuration key and client file.

```typescript theme={null}
// Using different connections
const pgClient = app.get('postgresClient')
const mongoClient = app.get('mongodbClient')
```

## Environment Variables

Connection strings can use environment variables in production:

```json config/production.json theme={null}
{
  "postgres": "postgres://$POSTGRES_USER:$POSTGRES_PASSWORD@$POSTGRES_HOST:5432/$POSTGRES_DATABASE"
}
```

<Warning>
  Never commit actual credentials to your repository. Use environment variables for sensitive connection information.
</Warning>

## Next Steps

<CardGroup cols={2}>
  <Card title="Generate a Service" icon="code" href="/cli/commands/service">
    Create a service that uses this database connection
  </Card>

  <Card title="Database Configuration" icon="database" href="/cli/configuration/database">
    Learn more about database configuration options
  </Card>
</CardGroup>