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ad hoc distributed queries Option

By default, SQL Server does not allow ad hoc distributed queries using OPENROWSET and OPENDATASOURCE. When this option is set to 1, SQL Server allows ad hoc access. When this option is not set or is set to 0, SQL Server does not allow ad hoc access.

Ad hoc distributed queries use the OPENROWSET and OPENDATASOURCE functions to connect to remote data sources that use OLE DB. OPENROWSET and OPENDATASOURCE should be used only to reference OLE DB data sources that are accessed infrequently. For any data sources that will be accessed more than several times, define a linked server.

Security noteSecurity Note

Enabling the use of ad hoc names means that any authenticated login to SQL Server can access the provider. SQL Server administrators should enable this feature for providers that are safe to be accessed by any local login. For more information, see the DisallowAdhocAccess option in Accessing External Data.

Examples

The following example enables ad hoc distributed queries and then queries a server named Seattle1 using the OPENROWSET function.

sp_configure 'show advanced options', 1;
RECONFIGURE;
sp_configure 'Ad Hoc Distributed Queries', 1;
RECONFIGURE;
GO

SELECT a.*
FROM OPENROWSET('SQLNCLI', 'Server=Seattle1;Trusted_Connection=yes;',
     'SELECT GroupName, Name, DepartmentID
      FROM AdventureWorks2008R2.HumanResources.Department
      ORDER BY GroupName, Name') AS a;
GO