For the majority of enterprises today, the bulk of mission-critical information resides on IBM mainframe and AS/400 computers. This information is stored in records on the OS/400 and VSAM file systems. This information is created by, owned by, and often accessible only by host-based applications. In the mainframe world these applications include CICS and DB2, other commercial applications, and a large number of custom applications written in COBOL, PL/I, and other languages. In the AS/400 world these applications include primarily DB2 and commercial applications, plus a large number of custom RPG applications. A key point to make is that not all of these data sources are SQL-accessible. Many of the host data stores contain non-SQL-accessible data that is owned by something other than a traditional relational database management system (RDBMS).
These same enterprises rely on vast networks of personal computers to enable their users to achieve business goals. End users invariably rely on PC network e-mail, Microsoft® Windows® productivity applications such as Microsoft® Office, and personal database programs such as Microsoft® Access, to accomplish their daily tasks. It is essential for these same users to incorporate data stored on host systems into their regular correspondence, analysis, and reports.
Available methods of accessing host data do not provide the granular "record-level" access required for cost-effective, secure, and meaningful integration of host and PC systems. In many cases, end users employ outright antiquated means of data integration. These methods include copying and pasting data from a terminal emulation screen, retyping information taken off printouts from host application reports, and importing text files containing comma-delimited values using host EBCDIC-to-PC ASCII file transfer. No one claims these methods are efficient, only that they are widely used, supported by products from independent software vendors (ISVs), and widely supported by information systems (IS) in general practice.
The challenge faced by IS professionals is how to provide direct record-level access to this valuable data without going through the host application. Much of the renewed interest in improved access to host data sources is a result of the burgeoning growth of local intranets, using the internal Internet, and web technology as mechanisms for delivering information. Fast and inexpensive methods of record-level access are needed in order to deliver modern three-tiered information systems during this era of cost-cutting and IS budget belt-tightening. Additional uses of this direct data access are ad hoc queries and web-based reporting, and a means to solve year 2000 issues. Corporate management frequently raises the issue of host data access as uncertainty over the year 2000 causes many managers to rethink host data storage. For many organizations, the answer to their year-2000 problems is in rewriting the arguably outdated and certainly "misdated" host-based business rules with server-based or even client-based business logic.
The goal of the OLE DB Provider for AS/400 and VSAM is to provide customers and solution providers with the means to integrate PC desktop applications with this wealth of data residing on host computers.