---
title: "Building a Knowledge Base"
ms.date: "07/31/2012"
ms.prod: sql
ms.prod_service: "data-quality-services"
ms.reviewer: ""
ms.technology: data-quality-services
ms.topic: conceptual
ms.assetid: 51eff161-6ecd-4ee4-8187-1dd8ef4814bd
author: swinarko
ms.author: sawinark
---
# Building a Knowledge Base

[!INCLUDE[appliesto-ss-xxxx-xxxx-xxx-md-winonly](../includes/appliesto-ss-xxxx-xxxx-xxx-md-winonly.md)]

  A knowledge base in [!INCLUDE[ssDQSnoversion](../includes/ssdqsnoversion-md.md)] (DQS) is a repository of knowledge about your data that enables you to understand your data and maintain its integrity. A knowledge base consists of domains, each of which represents the data in a data field. The knowledge base is used by DQS to perform data cleansing and deduplication on a database. To prepare the knowledge base for data cleansing, you can run a computer-assisted analysis of a data sample, and interactively manage values in the domains. DQS enables you to import knowledge, create rules and relationships, change data values directly, and leverage a default database.  
  
## In This Section  
 You can perform the following operations on a knowledge base:  
  
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|Create a new knowledge base from scratch, from an existing knowledge base, or from a .dqs data file.|[Create a Knowledge Base](../data-quality-services/create-a-knowledge-base.md)|  
|Open an existing knowledge base to perform knowledge discovery, domain management, or add a matching policy.|[Open a Knowledge Base](../data-quality-services/open-a-knowledge-base.md)|  
|Perform management actions on a knowledge base, including opening it, unlocking it, discarding your work on it, renaming it, deleting it, or viewing its properties.|[Manage a Knowledge Base](../data-quality-services/manage-a-knowledge-base.md)|  
|Add knowledge to a knowledge base through knowledge discovery; domain value management; adding a matching policy; importing a knowledge, domain, or values; or using the default knowledge base, DQS Data.|[Adding Knowledge to a Knowledge Base](../data-quality-services/adding-knowledge-to-a-knowledge-base.md)|  
|Analyze a data sample for data quality criteria.|[Perform Knowledge Discovery](../data-quality-services/perform-knowledge-discovery.md)|  
  
## Related Tasks  
  
|Task Description|Topic|  
|----------------------|-----------|  
|Importing knowledge into, or exporting it from, a knowledge base.|[Importing and Exporting Knowledge](../data-quality-services/importing-and-exporting-knowledge.md)|  
|Creating a single domain, and adding knowledge to the domain.|[Managing a Domain](../data-quality-services/managing-a-domain.md)|  
|Creating a composite domain, and adding knowledge to the domain.|[Managing a Composite Domain](../data-quality-services/managing-a-composite-domain.md)|