A set of open, extensible interfaces developed by Microsoft and based on OLE/COM technologies for providing applications with uniform methods of data access in diverse data sources.
These data sources can include mainframe databases such as IBM’s Information Management System (IMS) and DB2; server databases such as Microsoft SQL Server and Oracle; desktop databases such as Microsoft Access, Microsoft FoxPro, and Paradox; and non-DBMS information sources such as file systems, spreadsheets, text files, and e-mail. OLE DB defines interfaces that encapsulate various types of database functionality such as record containers, query processors, and transaction coordinators.
OLE DB facilitates the development of applications that combine various types of database queries from diverse sources.
The architecture of an OLE DB system has three parts:
Because of the standard set of interfaces used in OLE DB providers, any consumer is able to access data from any provider. Furthermore, because providers are COM objects, consumers can access them using any programming language, including C++, Microsoft Visual Basic, and Java.
Graphic O-2. The architecture of an OLE DB system.
As an example of a provider, the OLE DB Provider for AS/400 and VSAM enables record-level access to mainframe Virtual Storage Access Method (VSAM) files and to the AS/400 native file system. The OLE DB Provider for AS/400 and VSAM is included with Microsoft SNA Server version 4.
You use the OLE DB Provider for AS/400 and VSAM to develop applications for discrete data access and for record-level access to physical and logical files on AS/400 systems, in Partitioned Data Sets (PDS’s) and Partitioned Data Set Extended (PDSE) files, and in most versions of VSAM on mainframes.
Using the OLE DB Provider for AS/400 and VSAM, programmers can access mainframe VSAM or AS/400 data using Microsoft’s object-based OLE DB data access technology. Programmers can thus access source data from host systems without having to learn about Systems Network Architecture (SNA) or host applications programming.
The OLE DB Provider for AS/400 and VSAM facilitates a broad range of data access, from individual records to complete files. Using ActiveX Data Objects (ADO), you can develop web-to-host integration solutions using programming languages such as Microsoft Visual Basic or scripting languages such as Microsoft Visual Basic, Scripting Edition (VBScript), and Microsoft JScript.