--- title: "Determining Effective Database Engine Permissions | Microsoft Docs" ms.custom: "" ms.date: "01/03/2017" ms.prod: "sql-non-specified" ms.reviewer: "" ms.suite: "" ms.technology: - "database-engine" ms.tgt_pltfrm: "" ms.topic: "article" helpviewer_keywords: - "permissions, effective" - "effective permissions" ms.assetid: 273ea09d-60ee-47f5-8828-8bdc7a3c3529 caps.latest.revision: 5 author: "BYHAM" ms.author: "rickbyh" manager: "jhubbard" --- # Determining Effective Database Engine Permissions [!INCLUDE[tsql-appliesto-ss2008-all_md](../../../includes/tsql-appliesto-ss2008-all-md.md)] This topic describes how to determine who has permissions to various objects in the SQL Server Database Engine. SQL Server implements two permission systems for the Database Engine. An older system of fixed roles has preconfigured permissions. Beginning with SQL Server 2005 a more flexible and precise system is available. (The information in this topic applies to SQL Server, beginning with 2005. Some types of permissions are not available in some versions of SQL Server.) > [!IMPORTANT] > * The effective permissions are the aggregate of both permission systems. > * A denial of permissions overrides a grant of permissions. > * If a user is a member of the sysadmin fixed server role, permissions are not checked further, so denials will not be enforced. > * The old system and new system have similarities. For example, membership in the `sysadmin` fixed server role is similar to having `CONTROL SERVER` permission. But the systems are not identical. For example, if a login only has the `CONTROL SERVER` permission, and a stored procedures checks for membership in the `sysadmin` fixed server role, then the permission check will fail. The reverse is also true. ## Summary * Server-level permission can come from membership in the fixed server roles or user-defined server roles. Everyone belongs to the `public` fixed server role and receives any permission assigned there. * Server-level permissions can come from permission grants to logins or user-defined server roles. * Database-level permission can come from membership in the fixed database roles or user-defined database roles in each database. Everyone belongs to the `public` fixed database role and receives any permission assigned there. * Database-level permissions can come from permission grants to users or user-defined database roles in each database. * Permissions can be received from the `guest` login or `guest` database user if enabled. The `guest` login and users are disabled by default. * Windows users can be members of Windows groups which can have logins. SQL Server learns of Windows group membership when a Windows user connects and presents a Windows token with the security identifier of a Windows group. Because SQL Server does not manage or receive automatic updates about Windows group memberships, SQL Server cannot reliably report the permissions of Windows users that are received from Windows group membership. * Permissions can be acquired by switching to an application role and providing the password. * Permissions can be acquired by executing a stored procedure that includes the `EXECUTE AS` clause. * Permissions can be acquired by logins or users with the `IMPERSONATE` permission. * Members of the local computer administrator group can always elevate their privileges to `sysadmin`. (Does not apply to SQL Database.) * Members of the `securityadmin` fixed server role can elevate many of their privileges and in some cases can elevate the privileges to `sysadmin`. (Does not apply to SQL Database.) * SQL Server adminstrators can see information about all logins and users. Less priviledged users usually see information about only their own identities. ## Older Fixed Role Permission System Fixed Server Roles and Fixed Database Roles have preconfigured permissions that cannot be changed. To determine who is a member of a fixed server role, execute the following query. > [!NOTE] > Does not apply to SQL Database or SQL Data Warehouse where server level permission are not available. The `is_fixed_role` column of `sys.server_principals` was added in SQL Server 2012. It is not needed for older versions of SQL Server. ```tsql SELECT SP1.name AS ServerRoleName, isnull (SP2.name, 'No members') AS LoginName FROM sys.server_role_members AS SRM RIGHT OUTER JOIN sys.server_principals AS SP1 ON SRM.role_principal_id = SP1.principal_id LEFT OUTER JOIN sys.server_principals AS SP2 ON SRM.member_principal_id = SP2.principal_id WHERE SP1.is_fixed_role = 1 -- Remove for SQL Server 2008 ORDER BY SP1.name; ``` > [!NOTE] > * All logins are members of the public role and cannot be removed. > * This query checks tables in the master database but it can be executed in any database for the on premises product. To determine who is a member of a fixed database role, execute the following query in each database. ```tsql SELECT DP1.name AS DatabaseRoleName, isnull (DP2.name, 'No members') AS DatabaseUserName FROM sys.database_role_members AS DRM RIGHT OUTER JOIN sys.database_principals AS DP1 ON DRM.role_principal_id = DP1.principal_id LEFT OUTER JOIN sys.database_principals AS DP2 ON DRM.member_principal_id = DP2.principal_id WHERE DP1.is_fixed_role = 1 ORDER BY DP1.name; ``` To understand the permissions that are granted to each role, see the role descriptions at illustrations in Books Online ([Server-Level Roles](../../../relational-databases/security/authentication-access/server-level-roles.md), and [Database-Level Roles](../../../relational-databases/security/authentication-access/database-level-roles.md)). ## Newer Granular Permission System This system is extremely flexible, which means it can be complicated if the people setting it up want to be very precise. That's not necessarily bad; I hope my financial institution is precise. To simplify matters it helps to create roles, assign permissions to roles, and then add groups of people to the roles. And it's easier if the database development team separates activity by schema and then grants role permissions to a whole schema instead of to individual tables or procedures. But the real world is complex and we have to assume that business needs create unexpected security requirements. The following graphic shows the permissions and their relationships to each other. Some of the higher level permissions (such as `CONTROL SERVER`) are listed many times. In this topic, the poster is far to small to read. Click the image to download the **Database Engine Permissions Poster** in pdf format. [![Database Engine Permissions](../../../relational-databases/security/media/database-engine-permissions.PNG)](http://go.microsoft.com/fwlink/?LinkId=229142) ### Security Classes Permissions can be granted at the server-level, the database-level, the schema-level, or the object-level, etc. There are 26 levels (called classes). The complete list of classes in alphabetic order is: `APPLICATION ROLE`, `ASSEMBLY`, `ASYMMETRIC KEY`, `AVAILABILITY GROUP`, `CERTIFICATE`, `CONTRACT`, `DATABASE`, `DATABASE` `SCOPED CREDENTIAL`, `ENDPOINT`, `FULLTEXT CATALOG`, `FULLTEXT STOPLIST`, `LOGIN`, `MESSAGE TYPE`, `OBJECT`, `REMOTE SERVICE BINDING`, `ROLE`, `ROUTE`, `SCHEMA`, `SEARCH PROPERTY LIST`, `SERVER`, `SERVER ROLE`, `SERVICE`, `SYMMETRIC KEY`, `TYPE`, `USER`, `XML SCHEMA COLLECTION`. (Some classes are not available on some types of SQL Servers.) To provide full information about each class requires a different query. ### Principals Permissions are granted to principals. Principals can be server roles, logins, database roles, or users. Logins can represent Windows groups that include many Windows users. Since Windows groups are not maintained by SQL Server, SQL Server does not always know who is a member of a Windows group. When a Windows user connects to SQL Server, the login packet contains the Windows group membership tokens for the user. When a Windows user connects using a login based on a Windows group, some activities may require SQL Server to create a login or user to represent the individual Windows user. For example, a Windows group (Engineers) contains users (Mary, Todd, Pat) and the Engineers group has a database user account. If Mary has permission and creates a table, a user (Mary) might be created to be the owner of the table. Or if Todd is denied a permission that the rest of the Engineers group has, then the user Todd must be created to track the permission denial. Remember that a Windows user might be a member of more than one Windows group (e.g. both Engineers, and Managers). Permissions granted or denied to the Engineers login, to the Managers login, granted or denied to the user individually, and granted or denied to roles that the user is a member of, will all be aggregated and evaluated to for the effective permissions. The `HAS_PERMS_BY_NAME` function can reveal whether a user or login has a particular permission. However, there is no obvious way of determining the source of the grant or denial of permission. You must study the list of permissions and perhaps experiment using trial and error. ## Useful Queries ### Server Permissions The following query returns a list of the permissions that have been granted or denied at the server level. This query should be executed in the master database. > [!NOTE] > Server-level permissions cannot be granted or queried on SQL Database or SQL Data Warehouse. ```tsql SELECT pr.type_desc, pr.name, isnull (pe.state_desc, 'No permission statements') AS state_desc, isnull (pe.permission_name, 'No permission statements') AS permission_name FROM sys.server_principals AS pr LEFT OUTER JOIN sys.server_permissions AS pe ON pr.principal_id = pe.grantee_principal_id WHERE is_fixed_role = 0 -- Remove for SQL Server 2008 ORDER BY pr.name, type_desc; ``` ### Database Permissions The following query returns a list of the permissions that have been granted or denied at the database level. This query should be executed in each database. ```tsql SELECT pr.type_desc, pr.name, isnull (pe.state_desc, 'No permission statements') AS state_desc, isnull (pe.permission_name, 'No permission statements') AS permission_name FROM sys.database_principals AS pr LEFT OUTER JOIN sys.database_permissions AS pe ON pr.principal_id = pe.grantee_principal_id WHERE pr.is_fixed_role = 0 ORDER BY pr.name, type_desc; ``` Each class of permission the permission table can be joined to other system views that provide related information about that class of securable. For example, the following query provides the name of the database object that is affected by the permission. ```tsql SELECT pr.type_desc, pr.name, pe.state_desc, pe.permission_name, s.name + '.' + oj.name AS Object, major_id FROM sys.database_principals AS pr JOIN sys.database_permissions AS pe ON pr.principal_id = pe.grantee_principal_id JOIN sys.objects AS oj ON oj.object_id = pe.major_id JOIN sys.schemas AS s ON oj.schema_id = s.schema_id WHERE class_desc = 'OBJECT_OR_COLUMN'; ``` Use the `HAS_PERMS_BY_NAME` function to determine if a particular user (in this case `TestUser`) has a permission. For example: ```tsql EXECUTE AS USER = 'TestUser'; SELECT HAS_PERMS_BY_NAME ('dbo.T1', 'OBJECT', 'SELECT'); REVERT; ``` For the details of the syntax, see [HAS_PERMS_BY_NAME](../../../t-sql/functions/has-perms-by-name-transact-sql.md). ## See Also: [Getting Started with Database Engine Permissions](../../../relational-databases/security/authentication-access/getting-started-with-database-engine-permissions.md) [Tutorial: Getting Started with Database Engine](Tutorial:%20Getting%20Started%20with%20the%20Database%20Engine.md)