---
title: "Attach domain or composite domain to reference data"
description: Describes how to attach domains or composite domains in a data quality knowledge base with Data Quality Services (DQS) on SQL Server.
ms.custom: seo-lt-2019
ms.date: "03/01/2017"
ms.prod: sql
ms.prod_service: "data-quality-services"
ms.reviewer: ""
ms.technology: data-quality-services
ms.topic: conceptual
f1_keywords:
- "sql13.dqs.dm.refdata.f1"
- "sql13.dqs.dm.refcatalog.f1"
ms.assetid: 36af981c-d0d0-4dc6-afe5-bbb3c97845dc
author: swinarko
ms.author: sawinark
---
# Attach domain or composite domain to reference data - Data Quality Services (DQS)
[!INCLUDE[appliesto-ss-xxxx-xxxx-xxx-md-winonly](../includes/appliesto-ss-xxxx-xxxx-xxx-md-winonly.md)]
This topic describes how to attach domains/composite domains in a data quality knowledge base to a reference data service in Azure Marketplace to build knowledge against the high-quality reference data. Each reference data service contains a schema (data columns). After attaching a domain or a composite domain to a reference data service, you must map the attached domain or the individual domains within the attached composite domain to the appropriate columns in a reference data service schema. Attaching a composite domain to a reference data service enables you to attach just one domain to a reference data service, and then map the individual domains within the composite domain to appropriate columns in the reference data service schema.
> [!IMPORTANT]
> This article mentions third-party reference data services that were previously available from the Azure DataMarket. DataMarket and Data Services - including Melissa address data, for example - were discontinued after 12/31/2016. As a result, you can no longer run the examples in this article with the specified services from DataMarket. You can still use reference data services that are available directly online from third-party reference data providers.
> [!WARNING]
> The composite domain attached to a reference data service is available in the domains drop-down list while mapping domains to the columns in the reference data service schema. Do not map the composite domain to a column in the reference data service schema; you must only map individual domains within a composite domain to the appropriate columns in the reference data service schema. Otherwise, it will result in an error.
A reference data service schema can have a mandatory column that must be mapped with appropriate domain should you choose to use the reference data service. The mandatory column in a reference data schema is identified with "(M)" against the column name. For example, **AddressLine** is the mandatory schema column in **Melissa Data - Address Data** and **CompanyName** is the mandatory schema column in **Digital Trowel Inc. - Us companies and professional data for SQL users**.
In this topic, we will create four domains: **Address Line**, **City**, **State**, and **Zip**, under a composite domain, **Address Verification**, attach the composite domain to the **Melissa Data - Address Check** reference data service, and then map the individual domains within the composite domain to appropriate columns in the reference data service schema.
## Before You Begin
### Prerequisites
You must have configured [!INCLUDE[ssDQSnoversion](../includes/ssdqsnoversion-md.md)] (DQS) to use reference data services. See [Configure DQS to Use Reference Data](../data-quality-services/configure-dqs-to-use-reference-data.md).
### Security
#### Permissions
You must have the dqs_kb_editor role on the DQS_MAIN database to map domains to reference data.
## Map domains to reference data from Melissa Data
1. [!INCLUDE[ssDQSInitialStep](../includes/ssdqsinitialstep-md.md)] [Run the Data Quality Client Application](../data-quality-services/run-the-data-quality-client-application.md).
2. In the [!INCLUDE[ssDQSClient](../includes/ssdqsclient-md.md)] home screen, under **Knowledge Base Management**, click **New knowledge base**.
3. In the **New knowledge base** screen, type a name for the new knowledge base, click the **Domain Management** activity, and click **Create**.
4. In the **Domain Management** screen, click the **Create a domain** icon to create a domain. Create the following four domains: **Address Line**, **City**, **State**, and **Zip**.
5. Click the **Create a composite domain** icon to create a composite domain. In the **Create a composite domain** dialog box, type **Address Verification** in the **Composite Domain Name** box, and include all the domains created in step 3 in the composite domain. Click **OK**.
6. In the **Domain** pane on the left side, select the composite domain by clicking **Address Verification**, and then click the **Reference Data** tab on the right side.
7. Click the **Browse** icon.
8. In the **Online Reference Data Providers Catalog** dialog box:
1. Under **DataMarket Data Quality Services**, select the **Melissa Data - Address Check** box.
2. Map the columns of the Melissa Data - Address Check reference data service with the appropriate domains (Address Line, City, State, and Zip). You map the columns by selecting a reference data service column in the **RDS Schema** column, and then selecting the appropriate domain in the **Domain** column. To add more rows in the table, click the **Add Schema Entry** icon.
3. Click **OK** to save the changes, and close the **Online Reference Data Providers Catalog** dialog box.
> [!NOTE]
> - In the **Online Reference Data Providers Catalog** dialog box, the **DataMarket Data Quality Services** node displays all the reference data service providers that you have subscribed to in Azure Marketplace. If you have configured direct online third-party reference data service providers in DQS, they will appear under another node called **3rd Party Direct Online Providers** (not available now as no direct online third-party reference data service providers are configured in DQS).
9. You will return to the **Reference Data** tab. In the **Provider Settings** area, change values in the following boxes, if required:
- **Auto Correction Threshold**: Corrections from reference data service with confidence level above this threshold values will be automatically done. Enter a value in the decimal notation of the corresponding percentage value. For example, enter 0.9 for 90%.
- **Suggested Candidates**: Number of suggested candidates to display from the reference data service.
- **Min Confidence**: Suggestions from reference data service with confidence level lower than this value will be ignored. Enter a value in the decimal notation of the corresponding percentage value. For example, enter 0.6 for 60%.
10. Click **Finish** to publish the knowledge base. A confirmation message appears after the knowledge base is published successfully.
You can now use this knowledge base for cleansing activity in a data quality project to standardize and cleanse US addresses in your source data based on the knowledge provided by Melissa Data through Azure Marketplace.
## Follow Up: After Mapping a Domain to Reference Data
Create a data quality project, and run the cleansing activity on your source data containing US addresses by comparing it against the knowledge base created in this topic. See [Cleanse Data Using Reference Data (External) Knowledge](../data-quality-services/cleanse-data-using-reference-data-external-knowledge.md).
## See Also
[Reference Data Services in DQS](../data-quality-services/reference-data-services-in-dqs.md)
[Data Cleansing](../data-quality-services/data-cleansing.md)