AltimateAI · suryaiyer95 · Apr 2, 2026 · Apr 2, 2026 · Apr 6, 2026 · Apr 6, 2026
diff --git a/.opencode/skills/data-parity/SKILL.md b/.opencode/skills/data-parity/SKILL.md
@@ -71,6 +71,19 @@ WHERE table_schema = 'mydb' AND table_name = 'orders'
 ORDER BY ordinal_position
 ```
 
+```sql
+-- SQL Server / Fabric
+SELECT c.name AS column_name, tp.name AS data_type, c.is_nullable,
+       dc.definition AS column_default
+FROM sys.columns c
+INNER JOIN sys.types tp ON c.user_type_id = tp.user_type_id
+INNER JOIN sys.objects o ON c.object_id = o.object_id
+INNER JOIN sys.schemas s ON o.schema_id = s.schema_id
+LEFT JOIN sys.default_constraints dc ON c.default_object_id = dc.object_id
+WHERE s.name = 'dbo' AND o.name = 'orders'
+ORDER BY c.column_id
+```
+
 ```sql
 -- ClickHouse
 DESCRIBE TABLE source_db.events
@@ -409,3 +422,56 @@ Even when tables match perfectly, state what was checked:
 
 **Silently excluding auto-timestamp columns without asking the user**
 → Always present detected auto-timestamp columns (Step 4) and get explicit confirmation. In migration scenarios, `created_at` should be *identical* — excluding it silently hides real bugs.
+
+---
+
+## SQL Server and Microsoft Fabric
+
+### Minimum Version Requirements
+
+| Component | Minimum Version | Why |
+|---|---|---|
+| **SQL Server** | 2022 (16.x) | `DATETRUNC()` used for date partitioning; `LEAST()`/`GREATEST()` used by Rust engine |
+| **Azure SQL Database** | Any current version | Always has `DATETRUNC()` and `LEAST()` |
+| **Microsoft Fabric** | Any current version | T-SQL surface includes all required functions |
+| **mssql** (npm) | 12.0.0 | `ConnectionPool` isolation for concurrent connections, tedious 19 |
+| **@azure/identity** (npm) | 4.0.0 | Required only for Azure AD authentication; tedious imports it internally |
+
+> **Note:** Date partitioning (`partition_column` + `partition_granularity`) uses `DATETRUNC()` which is **not available on SQL Server 2019 or earlier**. Basic diff operations (joindiff, hashdiff, profile) work on older versions. If you need partitioned diffs on SQL Server < 2022, use numeric or categorical partitioning instead.
+
+### Supported Configurations
+
+| Warehouse Type | Authentication | Notes |
+|---|---|---|
+| `sqlserver` / `mssql` | User/password or Azure AD | On-prem or Azure SQL. SQL Server 2022+ required for date partitioning. |
+| `fabric` | Azure AD only | Microsoft Fabric SQL endpoint. Always uses TLS encryption. |
+
+### Connecting to Microsoft Fabric
+
+Fabric uses the same TDS protocol as SQL Server — no separate driver needed. Configuration:
+
+```yaml
+type: "fabric"
+host: "<workspace-id>-<item-id>.datawarehouse.fabric.microsoft.com"
+database: "<warehouse-name>"
+authentication: "azure-active-directory-default"   # recommended
+```
+
+Auth shorthands (mapped to full tedious type names):
+- `CLI` or `default` → `azure-active-directory-default`
+- `password` → `azure-active-directory-password`
+- `service-principal` → `azure-active-directory-service-principal-secret`
+- `msi` or `managed-identity` → `azure-active-directory-msi-vm`
+
+Full Azure AD authentication types:
+- `azure-active-directory-default` — auto-discovers credentials via `DefaultAzureCredential` (recommended; works with `az login`)
+- `azure-active-directory-password` — username/password with `azure_client_id` and `azure_tenant_id`
+- `azure-active-directory-access-token` — pre-obtained token (does **not** auto-refresh)
+- `azure-active-directory-service-principal-secret` — service principal with `azure_client_id`, `azure_client_secret`, `azure_tenant_id`
+- `azure-active-directory-msi-vm` / `azure-active-directory-msi-app-service` — managed identity
+
+### Algorithm Behavior
+
+- **Same-warehouse** MSSQL or Fabric → `joindiff` (single FULL OUTER JOIN, most efficient)
+- **Cross-warehouse** MSSQL/Fabric ↔ other database → `hashdiff` (automatic when using `auto`)
+- The Rust engine maps `sqlserver`/`mssql` to `tsql` dialect and `fabric` to `fabric` dialect — both generate valid T-SQL syntax with bracket quoting (`[schema].[table]`).
diff --git a/bun.lock b/bun.lock
diff --git a/packages/drivers/package.json b/packages/drivers/package.json
@@ -17,7 +17,7 @@
     "@google-cloud/bigquery": "^8.0.0",
     "@databricks/sql": "^1.0.0",
     "mysql2": "^3.0.0",
-    "mssql": "^11.0.0",
+    "mssql": "^12.0.0",
     "oracledb": "^6.0.0",
     "duckdb": "^1.0.0",
     "mongodb": "^6.0.0",

diff --git a/packages/drivers/src/normalize.ts b/packages/drivers/src/normalize.ts
@@ -65,6 +65,12 @@ const SQLSERVER_ALIASES: AliasMap = {
   ...COMMON_ALIASES,
   host: ["server", "serverName", "server_name"],
   trust_server_certificate: ["trustServerCertificate"],
+  authentication: ["authenticationType", "auth_type", "authentication_type"],
+  azure_tenant_id: ["tenantId", "tenant_id", "azureTenantId"],
+  azure_client_id: ["clientId", "client_id", "azureClientId"],
+  azure_client_secret: ["clientSecret", "client_secret", "azureClientSecret"],
+  access_token: ["token", "accessToken"],
+  azure_resource_url: ["azureResourceUrl", "resourceUrl", "resource_url"],
 }
 
 const ORACLE_ALIASES: AliasMap = {
@@ -104,6 +110,7 @@ const DRIVER_ALIASES: Record<string, AliasMap> = {
   mariadb: MYSQL_ALIASES,
   sqlserver: SQLSERVER_ALIASES,
   mssql: SQLSERVER_ALIASES,
+  fabric: SQLSERVER_ALIASES,
   oracle: ORACLE_ALIASES,
   mongodb: MONGODB_ALIASES,
   mongo: MONGODB_ALIASES,