Several independent software vendors (ISVs) have incorporated OLE DB as the data-access technology in their products. The ISVs, in turn, are making commitments to market OLE DB technology. Intersolv and ISG are two examples of ISVs that provide OLE DB-based solutions and that produce OLE DB components such as providers and service providers. For more information about ISVs building OLE DB providers, see www.microsoft.com/data/oledb/.
Data-access middleware based on OLE DB provides a data access tier, which buffers an application from the native interface of the data source, the location of the data source, and the data model. To the client application, the middleware presents a transparent interface and data model, regardless of the type and number of data sources.
Data-access middleware processes application requests for data from a variety of database types. It packages the requests and transports them to a specific server system, which handles the request. After processing the request, the middleware returns the data to the application.
The following are examples of the current middleware and third-party products available for data access.
ISG Navigator is universal data access middleware that provides access and manipulation of data residing on Windows and platforms other than Windows (such as OpenVMS and UNIX). ISG Navigator is OLE DB compliant, providing access to data sources such as hierarchical databases, indexed sequential files, simple files, personal databases, spreadsheets, and mail folders. By using ISG Navigator, nonrelational data can be accessed in the same way as relational data, that is, by using standard SQL.
ISG Navigator also allows heterogeneous queries, in where data from relational and nonrelational data sources can be integrated in a single query. ISG Navigator provides access to multiple data sources including SQL Server and Oracle.
Although ISG Navigator is designed natively for OLE DB, it also provides an ODBC interface so that application programs accessing data through ODBC can readily benefit from ISG Navigator. In other words, ISG Navigator appears to the application as an ODBC data source but, unlike other ODCB data sources, ISG Navigator encapsulates as one many data sources on multiple platforms. The ISG Navigator OLE DB query processor for Windows NT, together with its ODBC interface, is included in the Microsoft OLE DB software development kit (SDK) as ODBC Bridge.
Intersolv provides full support for the OLE DB initiative through its full-function ODBC solutions. The Intersolv DataDirect ODBC Drivers version 3.0 contains optimizations for use in the OLE DB environment. Intersolv is developing a series of OLE DB service providers and data providers.
Sequiter Software is developing an OLE DB provider for Xbase databases such as dBASE and Microsoft FoxPro. The Metawise Computing OLE DB providers, which use the IBM data access Distributed Data Management (DDM) protocol, work with AS/400 and virtual storage access method (VSAM) on Multiple Virtual Storage (MVS). These providers are included as part of the base system, with no host code required. MapInfo is releasing a client product with an OLE DB interface.