title: "sys.key_constraints (Transact-SQL) | Microsoft Docs" ms.custom: "" ms.date: "03/15/2017" ms.prod: "sql" ms.prod_service: "database-engine, sql-database, sql-data-warehouse, pdw" ms.service: "" ms.component: "system-catalog-views" ms.reviewer: "" ms.suite: "sql" ms.technology:
- "database-engine" ms.tgt_pltfrm: "" ms.topic: "language-reference" f1_keywords:
- "sys.key_constraints"
- "key_constraints"
- "sys.key_constraints_TSQL"
- "key_constraints_TSQL" dev_langs:
- "TSQL" helpviewer_keywords:
- "sys.key_constraints catalog view" ms.assetid: 0f782d2f-7126-46ab-85b7-bcba44862231 caps.latest.revision: 25 author: "edmacauley" ms.author: "edmaca" manager: "craigg" ms.workload: "Inactive" monikerRange: ">= aps-pdw-2016 || = azuresqldb-current || = azure-sqldw-latest || >= sql-server-2016 || = sqlallproducts-allversions"
[!INCLUDEtsql-appliesto-ss2008-all-md]
Contains a row for each object that is a primary key or unique constraint. Includes sys.objects.type PK and UQ.
| Column name | Data type | Description |
|---|---|---|
| <Columns inherited from sys.objects> | For a list of columns that this view inherits, see sys.objects (Transact-SQL). | |
| unique_index_id | int | ID of the corresponding unique index in the parent object that was created to enforce this constraint. |
| is_system_named | bit | 1 = Name was generated by system. 0 = Name was supplied by the user. |
[!INCLUDEssCatViewPerm] For more information, see Metadata Visibility Configuration.
Object Catalog Views (Transact-SQL)
Catalog Views (Transact-SQL)
Querying the SQL Server System Catalog FAQ