Introduction to SSAS Roles

SQL Server Analysis Services uses a role-based security model. You define roles, assign permissions to those roles, and then assign users or groups to those roles. This simplifies security management, especially in large environments.

Key benefits of using roles:

• Centralized Security: Manage security from a single point.
• Granular Control: Define precise access levels.
• Simplified Administration: Easier to add or remove user access.
• Data Security: Protect sensitive data from unauthorized access.

Types of Roles

There are two main types of roles in SSAS:

Database Roles

Database roles apply to a specific Analysis Services database. They control access to the objects within that database, such as cubes, dimensions, and mining structures.

Server Roles

Server roles apply to the Analysis Services instance itself. These are typically used for administrative tasks and have broad permissions across all databases on the server.

Creating Roles

Roles can be created using SQL Server Management Studio (SSMS) or by using XMLA (XML for Analysis) scripts.

Using SQL Server Management Studio (SSMS)

1. Connect to your Analysis Services instance in SSMS.
2. Right-click on the target database and select "New Role...".
3. In the "New Role" dialog box, provide a name for the role.
4. Configure the desired permissions on the "General" and "Data" tabs.
5. Add members to the role on the "Members" tab.
6. Click "OK" to create the role.

Using XMLA

You can script the creation of roles using XMLA. Here's a basic example:

<Create Object="Role">
  <ObjectDefinition>
    <Role xmlns="http://schemas.microsoft.com/analysisservices/2003/engine">
      <Name>SalesRead</Name>
      <DatabasePermissions>
        <Read>Allowed</Read>
        <ReadDefinition>Allowed</ReadDefinition>
      </DatabasePermissions>
      <Members>
        <Member>
          <Name>YourDomain\YourUser</Name>
        </Member>
      </Members>
    </Role>
  </ObjectDefinition>
</Create>
                

Understanding Permissions

Permissions define what actions members of a role can perform. Key permissions include:

• Read: Allows members to browse data within the database.
• ReadDefinition: Allows members to view the metadata of objects (e.g., cube structure, dimension definitions) but not the data itself.
• ReadAll: Allows members to read data and metadata for all objects in the database.
• Process: Allows members to process (refresh) objects within the database.
• Control: Allows members to manage roles and permissions.
• Administer: Grants full administrative control over the Analysis Services instance (typically for server roles).

For database roles, you can also define granular permissions on specific objects like cubes, dimensions, and perspectives. Additionally, you can implement Cell Security and Row-Level Security using MDX or DAX expressions.

Cell and Row-Level Security

These advanced security features allow you to restrict access to specific data cells or entire rows based on user context or other criteria.

• Cell Security: Define custom MDX or DAX expressions to filter data at the cell level.
• Row-Level Security: Restrict access to specific rows within a dimension based on user attributes.

Managing Role Members

Members can be added to roles using Windows user accounts, Windows groups, or custom security principals (though Windows accounts/groups are most common).

Adding Members

In SSMS, navigate to the role's properties, go to the "Members" tab, and click "Add...". You can then search for and add users or groups.

Best Practices

• Use Windows groups whenever possible. This allows you to manage permissions by managing group memberships in Active Directory, rather than directly within SSAS.
• Avoid granting permissions directly to individual users.

Processing Permissions

The "Process" permission is crucial for refreshing data within SSAS. Users with this permission can execute the Process command on cubes, dimensions, and other objects. This is typically required for ETL processes or scheduled data updates.

You can grant processing permissions at various levels:

• Database level (Process)
• Cube level (Process, ProcessFull, ProcessData, ProcessStructure)
• Dimension level (Process, ProcessFull, ProcessData, ProcessStructure)

Advanced Topics

Role Mining

Role mining is a technique to analyze user access patterns and suggest potential roles based on observed behavior. This can help in defining more effective security roles.

Integration with Other Microsoft Technologies

SSAS roles can be integrated with other security mechanisms, such as Active Directory security groups and SharePoint permissions, to create a comprehensive security solution.

Security Auditing

Regularly audit role memberships and permissions to ensure that security policies are being enforced and that there are no unauthorized access points.