With the retirement of Progress/400 DataServer, which was specially optimized for DB2/400 databases, many customers faced a very difficult decision of changing their strategy towards the AS/400 platform. In a great number of cases Progress 4GL/ADM2 programs were used as additional products running beside main, native AS/400 applications accessing mutual or separate DB2/400 database objects. Such implementations were usually determined by an existing IBM infrastructure on end user sites.
Obvious advantages of this platform, actively supported by IBM, bring about understandable reluctance to change it. Even though DB2/400 database, utilized by Progress 4GL application, can be easily migrated to a native Progress database on any other supported platform (Windows, UNIX), it doesn?t make it a viable solution in situations when there?s still a requirement to access AS/400 systems.
This is one of the reasons why there are still so many customers using ?old? Progress/400 9.1C implementations, in spite of the fact that the decision to retire the product was announced in 2001 (the retirement commenced in September 2003).
Before now, the only strategic options were: to leave the whole solution without any changes (taking advantage of the fact that Progress 9.1D and 9.1E clients could communicate with 9.1C DataServer), or move it to Progress native database. The most common choice was the first one. The introduction of OpenEdge 10.x DataServer for ODBC changes the current situation by offering another possibility for Progress Application deployment on the AS/400 platform. In fact, at this moment it becomes the only solution Progress Software is going to fully support.
OpenEdge DataServer for ODBC not only brings the opportunity to continue using Progress Applications with databases stored on the AS/400 systems but it also provides a new platform for better, more efficient, flexible and reliable implementations of distributed data processing that require access to UDB/400.
This article is meant to provide essential information on the underlying technology OpenEdge ODBC DataServer uses to let Progress applications manipulate data stored on iSeries. It gives an overview of the related communication layer and implementation architecture, which is necessary for successful adaptation in real environments. In particular, the article discusses the concept of Wire Protocol drivers, basics of DRDA (Distributed Relational Database Architecture) connection over TCP/IP, and general aspects of accessing UDB/400 through SQL/400 and the ODBC API.
DB2 for AS400 via OpenEdge DataServer for OSBC.pdf