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

# Connecting to multiple data sources

> Manage one or more data source connections per Cube Cloud deployment from a single place.

A Cube Cloud deployment always has a single **default** data source plus,
optionally, one or more **named** data sources. [Cubes](/reference/data-modeling/cube)
reference whichever source they need via the
[`data_source`](/reference/data-modeling/cube#data_source) property.

Manage data sources from your deployment's **Settings → Data Sources** page.

## Adding a data source

Click **+ Add data source**, pick the driver, give the source a short
name (see [Source name rules](#source-name-rules)), and fill in the
connection form — the same form the deployment wizard uses.

Cube Cloud tests the connection before saving; on success it persists the
env vars and restarts the development environment, on failure it surfaces
the driver's error and saves nothing.

## Editing and deleting

Use the **Edit** action on a row to update credentials, or the **Delete**
action to remove a named source. The **default** source can be edited but
not deleted — to remove it, clear the bare `CUBEJS_DB_*` variables from
[**Settings → Environment Variables**][ref-config-ref-env] by hand.

## Source name rules

* Letters, digits, and underscores; must start with a letter.
* `default` is reserved; use the **Use as default** button on the naming
  step instead.
* Flat names (`analytics`, `warehouse`) are safer than names with
  underscores, which can collide with the env-var parser when they end in
  `_db`, `_aws`, or `_jdbc`.

## Using a data source from a cube

Reference a source from the
[`data_source`](/reference/data-modeling/cube#data_source) property using
the name you gave it when you created it:

<CodeGroup>
  ```yaml title="YAML" theme={"dark"}
  cubes:
    - name: orders_from_other_data_source
      # ...
      data_source: analytics
  ```

  ```javascript title="JavaScript" theme={"dark"}
  cube(`orders_from_other_data_source`, {
    // ...
    data_source: `analytics`
  })
  ```
</CodeGroup>

Cubes that don't set `data_source` use the default source — there's no
need to write `data_source: default` explicitly, though you can if you
prefer to be explicit.

For multitenancy scenarios where the data source is selected dynamically
per request, see [`driver_factory`](/reference/configuration/config#driver_factory)
and the [multitenancy guide][ref-config-multitenancy].

## Workbooks

Sources show up immediately in
[Workbooks](/docs/explore-analyze/workbooks) — open a
[Source SQL tab](/docs/explore-analyze/workbooks/source-sql-tabs) and they
appear in the data sources sidebar without needing a cube to reference
them first.

## Under the hood

The UI is a friendlier surface over the deployment's environment
variables — inspect or hand-edit them from
[**Settings → Environment Variables**][ref-config-ref-env] at any time.

The default source uses bare `CUBEJS_DB_*` variables; each named source
uses a `CUBEJS_DS_<NAME>_*` prefix. `CUBEJS_DATASOURCES` is auto-maintained
whenever at least one named source exists, with `default` first and named
entries lowercased:

```dotenv theme={"dark"}
CUBEJS_DATASOURCES=default,analytics
CUBEJS_DB_TYPE=postgres
CUBEJS_DB_HOST=localhost
CUBEJS_DS_ANALYTICS_DB_TYPE=postgres
CUBEJS_DS_ANALYTICS_DB_HOST=remotehost
```

For the full list of variables that support decoration, see the
[environment variables reference][ref-config-ref-env].

Each source can also build and store its pre-aggregations on a dedicated connection
using the `CUBEJS_DS_<NAME>_PRE_AGGREGATIONS_DB_*` variables. See [pre-aggregation data
source][ref-preagg-data-source] for details.

[ref-config-ref-env]: /reference/configuration/environment-variables

[ref-preagg-data-source]: /docs/pre-aggregations/refreshing-pre-aggregations#pre-aggregation-data-source

[ref-config-multitenancy]: /embedding/multitenancy#multitenancy-multitenancy-vs-multiple-data-sources