Microsoft SQL Server Compatibility With ODBC

In this section:

Release 5.2 and higher of the Adapter for Microsoft SQL Server is based on OLE DB, the Microsoft-recommended API for developing high-performance components. The adapter uses the OLE DB Provider for SQL Server (SQLOLEDB), a native, high-performance provider that directly accesses the SQL Server TDS protocol.

Releases of the adapter prior to 5.2 were based on the ODBC API. The current release of the adapter supports all the functionality of the earlier, ODBC-based versions. In addition, it introduces the following enhancements:

Differences between adapter functionality under OLE DB and ODBC exist in the following areas:

If you are using ODBC, be sure to review these topics.


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Microsoft SQL Server Connection Attributes With ODBC

An ODBC data source declaration contains the following information: the instance of Microsoft SQL Server, the default database, the network libraries, and so on. In earlier, ODBC-based releases of the adapter, the SET CONNECTION_ATTRIBUTES command required only the name of an ODBC data source (User or System DNS) and authentication parameters.

Unlike ODBC data sources, OLE DB data sources directly reference instances of Microsoft SQL Server. To connect to an OLE DB data source, the adapter has to specify all the pertinent parameters at connection time. For this reason, the syntax of the How to Declare Connection Attributes Manually on UNIX and z/OS command has been expanded to account for these parameters and also to provide the ability to declare more than one connection to the same instance of Microsoft SQL Server.


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Microsoft SQL Server Cursors With ODBC

In earlier, ODBC-based releases of the adapter, the SET parameter CONCUR is used to control the ODBC cursor type. The CONCUR parameter has two settings: RONLY results in client-side cursors, and ROWVER forces cursors to be server-side. Release 5.2 of the adapter takes advantage of OLE DB's ability to directly control the cursor type using a CURSOR parameter. The SET parameter CURSOR has two settings: CLIENT and SERVER. By default, the adapter assigns cursor properties that provide maximum performance for the given environment.


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Mapping of UNIQUEIDENTIFIER and BIT Data Types

OLE DB maps the following data types differently than ODBC:


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