# Source: https://docs.turso.tech/features/attach-database.md

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.turso.tech/llms.txt
> Use this file to discover all available pages before exploring further.

# Attach Database (Deprecated)

> Attach and read data across multiple databases.

<Warning>
  This feature is now deprecated for all new users. Existing paid users can
  continue to use `ATTACH` — [read the
  announcement](https://turso.tech/blog/upcoming-changes-to-the-turso-platform-and-roadmap)
</Warning>

The `ATTACH` statement enables you to link multiple databases within a single transaction, which is ideal for:

* Organizing data in a modular way
* Streamlining data access and enhancing scalability
* Aggregating data

## How it works

1. You enable the `ATTACH` feature on the databases you want to connect to.
2. You retrieve the **Database ID** for the database you want to `ATTACH`.
3. You connect to the database
   * **CLI**: `--attach` flag to automatically create a token with the correct permissions.
   * **SDK**: Create a token with the `attach` permission for the database you want to attach.
4. You invoke `ATTACH` to connect to the other databases within the database shell or SDK.

## Usage

You can use the `ATTACH` statement to connect to other databases within a transaction using the CLI, or libSQL SDK. Once attached, you can query the attached databases as if they were part of the current database using the assigned alias.

### Turso CLI

Make sure you have the [Turso CLI](/cli/installation) installed, and [logged in](/cli/auth/login).

<Steps>
  <Step title="Enable attach on required databases">
    You will first need to enable the `ATTACH` feature on the database(s) you want to attach:

    ```bash  theme={null}
    turso db config attach allow <database-name>
    ```
  </Step>

  <Step title="Retrieve Database ID">
    You now need to retrieve the **Database ID** for the database you want to `ATTACH`:

    ```bash  theme={null}
    turso db show <database-name>
    ```
  </Step>

  <Step title="Connect to any database with attach">
    Now pass the names of the databases via the `--attach` flag when connecting to your database(s):

    ```bash  theme={null}
    turso db shell <database-name> --attach <...database-name(s)>
    ```
  </Step>

  <Step title="ATTACH">
    Now once connected to the database you can invoke an `ATTACH` statement to connect the other database(s):

    ```sql  theme={null}
    ATTACH "<database-id>" AS my_db;
    ```
  </Step>

  <Step title="Query">
    Execute a query using the alias for any attached database(s):

    ```sql  theme={null}
    SELECT * FROM my_db.my_table;
    ```
  </Step>
</Steps>

### libSQL SDKs

You can use one of the libSQL client SDKs with [TypeScript](/sdk/ts), [Rust](/sdk/rust), [Go](/sdk/go), [Python](/sdk/python), or over [HTTP](/sdk/http).

<Steps>
  <Step title="Enable attach on required databases">
    You will first need to enable the `ATTACH` feature on the database(s) you want to attach:

    ```bash  theme={null}
    turso db config attach allow <database-name>
    ```
  </Step>

  <Step title="Retrieve Database ID">
    You now need to retrieve the **Database ID** for the database you want to `ATTACH`:

    ```bash  theme={null}
    turso db show <database-name>
    ```
  </Step>

  <Step title="Create token with ATTACH permissions">
    Now create a token for the libSQL client with the `attach` permission for the database you want to attach:

    ```bash  theme={null}
    turso db tokens create <database-name> --attach <another-database-name>
    ```
  </Step>

  <Step title="Connect to any database with ATTACH">
    Use a [Client SDK](/sdk) to attach the desired database within a read transaction:

    <CodeGroup>
      ```ts @libsql/client theme={null}
      import { createClient } from "@libsql/client";

      const client = createClient({
        syncUrl: "libsql://...",
        authToken: "...",
      });

      const txn = await db.transaction("read");

      await txn.execute('ATTACH "<database-id>" AS my_db');

      const rs = await txn.execute("SELECT * FROM my_db.my_table");
      ```
    </CodeGroup>
  </Step>
</Steps>

## Things to know

* You can only attach databases that have the `attach` feature enabled.
* You can only attach databases belonging to a group, and in the same group.
* There is a maximum of 10 databases that can be attached to a single transaction.
* The attached databases are read only.
* `ATTACH` statement can be used only within transactions.
* `ATTACH` doesn't support [Embedded Replicas](/features/embedded-replicas)