OpenDataSource 使用ad hoc 链接信息链接到Remote Data Source，而不是使用Linked Server，而OpenDataSource Row Set函数的作用是在使用 four-part object name 定位一个object时，提供ServerName\InstanceName。SQL Server 任何一个Object完全指定的命名结构依次是:Server Name，Instance Name，Database name，Schema Name，Object name。
Provides ad hoc connection information as part of a four-part object name without using a linked server name.
Openquery 函数是不确定性的函数，就是说，对于相同的输入值，不保证每次返回的值都是相同的。
All rowset functions are nondeterministic. This means these functions do not always return the same results every time they are called, even with the same set of input values.
Syntax
OPENDATASOURCE ( provider_name, init_string )
Arguments
- provider_name
-
Is the name registered as the PROGID of the OLE DB provider used to access the data source. provider_name is a char data type, with no default value. - init_string
-
Is the connection string passed to the destination provider. The provider string syntax is based on keyword-value pairs separated by semicolons, such as: ‘keyword1=value; keyword2=value‘.For specific keyword-value pairs supported on the provider, see the Microsoft Data Access SDK. This documentation defines the basic syntax. The following table lists the most frequently used keywords in the init_string argument.
Keyword
OLE DB property
Valid values and description
Data Source
DBPROP_INIT_DATASOURCE
Name of the data source to connect to. Different providers interpret this in different ways. For SQL Server Native Client OLE DB provider, this indicates the name of the server. For Jet OLE DB provider, this indicates the full path of the .mdb file or .xls file.
Location
DBPROP_INIT_LOCATION
Location of the database to connect to.
Extended Properties
DBPROP_INIT_PROVIDERSTRING
The provider-specific connect-string.
Connect timeout
DBPROP_INIT_TIMEOUT
Time-out value after which the connection try fails.
User ID
DBPROP_AUTH_USERID
User ID to be used for the connection.
Password
DBPROP_AUTH_PASSWORD
Password to be used for the connection.
Catalog
DBPROP_INIT_CATALOG
The name of the initial or default catalog when connecting to the data source.
Integrated Security
DBPROP_AUTH_INTEGRATED
SSPI, to specify Windows Authentication
Remarks
OPENDATASOURCE can be used to access remote data from OLE DB data sources only when the DisallowAdhocAccess registry option is explicitly set to 0 for the specified provider, and the Ad Hoc Distributed Queries advanced configuration option is enabled. When these options are not set, the default behavior does not allow for ad hoc access.
The OPENDATASOURCE function can be used in the same Transact-SQL syntax locations as a linked-server name. Therefore, OPENDATASOURCE can be used as the first part of a four-part name that refers to a table or view name in a SELECT, INSERT, UPDATE, or DELETE statement, or to a remote stored procedure in an EXECUTE statement. When executing remote stored procedures, OPENDATASOURCE should refer to another instance of SQL Server. OPENDATASOURCE does not accept variables for its arguments.
Like the OPENROWSET function, OPENDATASOURCE should only reference OLE DB data sources that are accessed infrequently. Define a linked server for any data sources accessed more than several times. Neither OPENDATASOURCE nor OPENROWSET provide all the functionality of linked-server definitions, such as security management and the ability to query catalog information. All connection information, including passwords, must be provided every time that OPENDATASOURCE is called.
Example
SELECT *
FROM OPENDATASOURCE(‘SQLNCLI‘,
‘Data Source=London\Payroll;Integrated Security=SSPI‘)
.AdventureWorks2012.HumanResources.Employee
SELECT * FROM OPENDATASOURCE(‘Microsoft.Jet.OLEDB.4.0‘,
‘Data Source=C:\DataFolder\Documents\TestExcel.xls;Extended Properties=EXCEL 5.0‘)...[Sheet1$] ;
引用文档：MSDN OPENDATASOURCE (Transact-SQL)