> ## 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.

# Microsoft SQL Server

> Connect Cube to SQL Server with database host credentials, optional domain-scoped login, and SSL or pool tuning as needed.

## Prerequisites

* The hostname for the [Microsoft SQL Server][mssql] database server
* The username/password for the [Microsoft SQL Server][mssql] database server
* The name of the database to use within the [Microsoft SQL Server][mssql]
  database server

## Setup

### Manual

Add the following to a `.env` file in your Cube project:

```dotenv theme={"dark"}
CUBEJS_DB_TYPE=mssql
CUBEJS_DB_HOST=my.mssql.host
CUBEJS_DB_NAME=my_mssql_database
CUBEJS_DB_USER=mssql_user
CUBEJS_DB_PASS=**********
```

## Environment Variables

| Environment Variable                                                                                                        | Description                                                                                                                 | Possible Values                                            | Required |
| --------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------- | :------: |
| [`CUBEJS_DB_HOST`](/reference/configuration/environment-variables#cubejs_db_host)                                           | The host URL for a database                                                                                                 | A valid database host URL                                  |     ✅    |
| [`CUBEJS_DB_PORT`](/reference/configuration/environment-variables#cubejs_db_port)                                           | The port for the database connection                                                                                        | A valid port number                                        |     ❌    |
| [`CUBEJS_DB_NAME`](/reference/configuration/environment-variables#cubejs_db_name)                                           | The name of the database to connect to                                                                                      | A valid database name                                      |     ✅    |
| [`CUBEJS_DB_USER`](/reference/configuration/environment-variables#cubejs_db_user)                                           | The username used to connect to the database                                                                                | A valid database username                                  |     ✅    |
| [`CUBEJS_DB_PASS`](/reference/configuration/environment-variables#cubejs_db_pass)                                           | The password used to connect to the database                                                                                | A valid database password                                  |     ✅    |
| [`CUBEJS_DB_DOMAIN`](/reference/configuration/environment-variables#cubejs_db_domain)                                       | A domain name within the database to connect to                                                                             | A valid domain name within a Microsoft SQL Server database |     ❌    |
| [`CUBEJS_DB_SSL`](/reference/configuration/environment-variables#cubejs_db_ssl)                                             | If `true`, enables SSL encryption for database connections from Cube                                                        | `true`, `false`                                            |     ❌    |
| [`CUBEJS_DB_MAX_POOL`](/reference/configuration/environment-variables#cubejs_db_max_pool)                                   | The maximum number of concurrent database connections to pool. Default is `8`                                               | A valid number                                             |     ❌    |
| [`CUBEJS_DB_MSSQL_USE_NAMED_TIMEZONES`](/reference/configuration/environment-variables#cubejs_db_mssql_use_named_timezones) | The flag to use time zone names (with DST-aware conversion) or numeric offsets for time zone conversion. Default is `false` | `true`, `false`                                            |     ❌    |
| [`CUBEJS_CONCURRENCY`](/reference/configuration/environment-variables#cubejs_concurrency)                                   | The number of [concurrent queries][ref-data-source-concurrency] to the data source                                          | A valid number                                             |     ❌    |

[ref-data-source-concurrency]: /admin/connect-to-data/concurrency#data-source-concurrency

## Pre-Aggregation Feature Support

### count\_distinct\_approx

Measures of type
[`count_distinct_approx`][ref-schema-ref-types-formats-countdistinctapprox] can
not be used in pre-aggregations when using Microsoft SQL Server as a source
database.

## Pre-Aggregation Build Strategies

<Info>
  To learn more about pre-aggregation build strategies, [head
  here][ref-caching-using-preaggs-build-strats].
</Info>

| Feature       | Works with read-only mode? | Is default? |
| ------------- | :------------------------: | :---------: |
| Simple        |              ✅             |      ✅      |
| Batching      |              -             |      -      |
| Export Bucket |              -             |      -      |

By default, Microsoft SQL Server uses a [simple][self-preaggs-simple] strategy
to build pre-aggregations.

### Simple

No extra configuration is required to configure simple pre-aggregation builds
for Microsoft SQL Server.

### Batching

Microsoft SQL Server does not support batching.

### Export Bucket

Microsoft SQL Server does not support export buckets.

## SSL

To enable SSL-encrypted connections between Cube and Microsoft SQL Server, set
the [`CUBEJS_DB_SSL`](/reference/configuration/environment-variables#cubejs_db_ssl) environment variable to `true`. For more information on how
to configure custom certificates, please check out [Enable SSL Connections to
the Database][ref-recipe-enable-ssl].

## Additional Configuration

### Windows Authentication

To connect to a Microsoft SQL Server database using Windows Authentication (also
sometimes known as `trustedConnection`), instantiate the driver with
`trustedConnection: true` in your `cube.js` configuration file:

```javascript theme={"dark"}
const MssqlDriver = require("@cubejs-backend/mssql-driver")
module.exports = {
  driverFactory: ({ dataSource }) =>
    new MssqlDriver({ database: dataSource, trustedConnection: true })
}
```

[mssql]: https://www.microsoft.com/en-gb/sql-server/sql-server-2019

[ref-caching-using-preaggs-build-strats]: /docs/pre-aggregations/using-pre-aggregations#pre-aggregation-build-strategies

[ref-recipe-enable-ssl]: /recipes/configuration/using-ssl-connections-to-data-source

[ref-schema-ref-types-formats-countdistinctapprox]: /reference/data-modeling/measures#type

[self-preaggs-simple]: #simple