By: Eli Leiba | Last Updated: 2019-04-11 | Comments (1) | Security
Using SQL Server database roles, in my opinion, is the simplest security method to assign and manage user permissions. I think this is the most common method that Database Administrators (DBA) use to handle permissions using either fixed database roles or creating user-defined database roles. This comes from over two decades of doing SQL database administration work.
Traditionally SQL Server provides two types of database-level roles: fixed-database roles that are predefined in the database and user-defined database roles that you can create. The database roles are defined at the database level and exist on each database. When the DBA maps the logins to databases, he/she can also create members of these database roles that manage the security in the database.
To help illustrate the fixed database roles, below is an image that explains them (this is from Microsoft MSDN, https://docs.microsoft.com/en-us/sql/relational-databases/security/authentication-access/database-level-roles?view=sql-server-2017).
In SQL Server Management Studio (SSMS), when you click the user mapping tab, you can assign any database role in the database to a user, but you cannot see in a single screen all of the database roles assigned to each database user. In order to do that you must click on every user line and "collect" the database roles assigned to each user. Therefore, there is a need for a simple T-SQL tool that generates a "database users to database roles mapping", this tool should be able to map all the database roles or to focus on a single role.
My solution involves creating a simple T-SQL in-line table function that generates a users to database roles mapping. This function should be created and used in each application database.
The function gets one parameter containing the database role name. If the report is called to retrieve all database role mappings then it defaults to a value of '%' (meaning all values).
This function (dbo.dbRolesUsersMap) joins to (according to the system relationship model) three system tables:
|sys.database_role_members s||This system table returns one row on each member of each database role. Database users, application roles, and other database roles can be members of a database role|
|sys.database_principals||This system table returns a row for each security principal in a SQL Server database|
|Sys.server_principals||This system table Contains a row for every server-level principal|
The function distinguishes between three main user types: SQL user, Windows user and Windows group. It focuses only on database user roles and filters out system and INFORMATION_SCHEMA roles from the result.
The function shows the following columns:
- The user type (Windows group / Windows user/ SQL user)
- The database user name
- The server login name associated with that user
- The assigned database role name
SQL Server Function to Show Users to Database Roles Mapping
SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO -- ================================================ -- Author: Eli Leiba -- Create date: 24-03-2019 -- Description: Simple Users to Database Roles mappings function -- ================================================ CREATE FUNCTION dbo.dbRolesUsersMap (@dbRole SYSNAME = '%') RETURNS TABLE AS RETURN ( SELECT User_Type = CASE mmbrp.[type] WHEN 'G' THEN 'Windows Group' WHEN 'S' THEN 'SQL User' WHEN 'U' THEN 'Windows User' END, Database_User_Name = mmbrp.[name], Login_Name = ul.[name], DB_Role = rolp.[name] FROM sys.database_role_members mmbr, -- The Role OR members associations table sys.database_principals rolp, -- The DB Roles names table sys.database_principals mmbrp, -- The Role members table (database users) sys.server_principals ul -- The Login accounts table WHERE Upper (mmbrp.[type]) IN ( 'S', 'U', 'G' ) -- No need for these system account types AND Upper (mmbrp.[name]) NOT IN ('SYS','INFORMATION_SCHEMA') AND rolp.[principal_id] = mmbr.[role_principal_id] AND mmbrp.[principal_id] = mmbr.[member_principal_id] AND ul.[sid] = mmbrp.[sid] AND rolp.[name] LIKE '%' + @dbRole + '%' ) GO
Sample Execution with the SQL Server In-Line Table Function
Generate the users to database roles mapping for the entire NorthwindTrainingDB database.
USE NorthwindTrainingDB GO SELECT * FROM dbo.dbRolesUsersMap (DEFAULT) GO
Here are the results (on my server):
Generate only the users to database roles mapped to the db_ddlAdmin role in the NorthwindTrainingDB database.
USE NorthwindTrainingDB GO SELECT * FROM dbo.dbRolesUsersMap ('db_ddlAdmin') GO
Here are the results (on my server):
- You can create and compile this simple function in each of your application databases and use it as a simple tool to generate a fast database user to database roles reports.
- Note that the function is not limited to only the fix database roles. If user defined database roles exist and map to a user then it will show on the report, but its inner permission will be absent from the report.
- The function was tested with for SQL Server 2014 and 2017, but it uses general SQL Server tables and functions so it should be compatible with SQL Server 2008 and above. The security system objects: sys.server_principals, sys.database_principals and sys.database_role_members all started with the SQL Server 2008 version.
Last Updated: 2019-04-11
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