This article was previously published under Q244661
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This article describes the limitations of the current version of Microsoft ODBC Driver and OLE DB Provider for Oracle. These components are currently in maintenance mode. No new updates are planned for future releases of these components including their support against versions later than Oracle 8i.
The current version of the Microsoft ODBC Driver for Oracle complies with the ODBC 2.5 specification, while the OLE DB Provider for Oracle is a native Oracle 7 OCI API provider. Both the driver and provider make OCI 7 API calls against the Oracle client components regardless of the Oracle version installed on the computer.
From Microsoft Data Access Components (MDAC) version 2.5 and later versions, both the Microsoft ODBC Driver and OLE DB Provider support ONLY Oracle 7 and Oracle 8i with the following limitations:
Oracle 8.x-specific data types, such as CLOB, BLOB, BFILE, NCHAR, NCLOB, and NVARCHAR2, are not supported.
The Unicode feature against Oracle 7.x and 8.x servers is not supported.
Multiple Oracle client instances, or multiple Oracle homes, are not supported because they rely on the first occurrence of the Oracle home in the SYSTEM PATH variable.
Returning multiple resultsets from a stored procedure or batch SQL statement is not supported using ADO or OLEDB.For additional information about how to retrieve a resultset from an Oracle stored procedure, click the following article numbers to view the articles in the Microsoft Knowledge Base:
255043 How to retrieve ADO recordset from Oracle through ASP using REF CURSORS
176086 HOWTO: Retrieve Recordsets from Oracle Stored Procs Using ADO
Nested outer joins are not supported.
XML persistence is not supported.
Version greater than 8i are not supported using this drivers.
For additional information, see the Help file that is included with the driver and provider.For additional information, click the following article numbers to view the articles in the Microsoft Knowledge Base:
259959 Techniques to debug connectivity issues to an Oracle server using the ODBC Driver and OLE DB Provider
280106 How to set up and troubleshoot a linked server to Oracle in SQL Server
306787 PRB: Returning multiple resultsets fails under ADO with Microsoft Oracle OLEDB Provider and ODBC Driver
The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.
Microsoft Data Access Components 2.5, Microsoft Data Access Components 2.6, Microsoft Data Access Components 2.7, Microsoft ODBC for Oracle (Build 2.573.7626) 2.5, Microsoft OLE DB Provider for Oracle Server 1.0, Microsoft OLE DB Provider for Oracle Server 1.0, Microsoft OLE DB Provider for Oracle Server 1.0