> For the complete documentation index, see [llms.txt](https://metalbear.com/mirrord/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://metalbear.com/mirrord/docs/sharing-the-cluster/db-branching/mssql.md).

# MSSQL

This page covers DB branching for Microsoft SQL Server (MSSQL). For the general concepts, the full list of config fields, and how a session behaves, see the [DB Branching overview](/mirrord/docs/sharing-the-cluster/db-branching.md).

{% hint style="info" %}
MSSQL branching requires operator `3.150.0`, mirrord CLI `3.195.0`, and operator Helm chart `1.57.0` with the `operator.mssqlBranching` value set to `true`.
{% endhint %}

### Basic Configuration

```json
{
  "feature": {
    "db_branches": [
      {
        "id": "users-mssql-db",
        "type": "mssql",
        "version": "2022-latest",
        "name": "users-database-name",
        "connection": {
          "url": "DATABASE_URL"
        },
        "copy": {
          "mode": "empty"
        }
      }
    ]
  }
}
```

The `connection` field describes how mirrord locates the source database connection details - a full connection URL or individual parameters (host, port, user, password, database). See [Connection Modes](/mirrord/docs/sharing-the-cluster/db-branching/more/connection.md) for all supported sources, including Kubernetes Secrets, Google Secret Manager, literal values, and composite environment variables.

### Copy Modes

The `copy` field controls what data gets cloned when creating an MSSQL branch.

| Mode                | What gets cloned                                                               | Best for                                                                                      |
| ------------------- | ------------------------------------------------------------------------------ | --------------------------------------------------------------------------------------------- |
| `"empty"` (default) | Nothing - an empty database with no schema or data                             | Workflows where your application initializes the schema or runs migrations as part of startup |
| `"schema"`          | Only the table structures (schemas) from the source database, without any data | Testing schema changes or local development where structure is needed but data is not         |
| `"all"`             | Everything from the source database - both schema and data                     | A full clone of your environment data for debugging or reproducing production-like scenarios  |

{% hint style="warning" %}
Use `"mode": "all"` with caution. It’s only recommended for very small or empty databases. Copying large datasets can significantly increase branch creation time and storage usage.
{% endhint %}

#### Filtered Data Clone

Developers can customize what gets copied per table. This allows copying only specific rows or subsets of data using SQL query filters.

```json
{
  "copy": {
    "mode": "schema",                   // Or "empty" as explained below
    "tables": {
      "users": {
        "filter": "name = 'alice' OR name = 'bob'"
      },
      "orders": {
        "filter": "created_at > 1759948761"
      }
    }
  }
}
```

**In this example**

The schema for all tables is cloned. The `users` table copy includes only rows for `alice` and `bob`. The `orders` table copy includes only rows created after a certain timestamp.

Filtering can also be combined with `"mode": "empty"`, in which case only the specified tables (and their filtered data) are copied, while all others are excluded.

Note: Filtering is not compatible with `"mode": "all"`. If both are specified, mirrord ignores the `tables` configuration.

{% hint style="info" %}
The `dump_args` field is not supported for MSSQL. MSSQL branches use their own internal dump mechanism, so only MySQL and PostgreSQL branches accept custom dump arguments.
{% endhint %}


---

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