IBM pushes DRDA link to relational data; DRDA is key to Information Warehouse framework, but skeptics claim the architecture is proprietary - Distributed Relational Database Architecture - SAA: Data Management Update

Software Magazine, Nov 15, 1991 by Mary Alice Hanna

With its latest Systems Application Architecture (SAA) framework. Information Warehouse, IBM promises access to many third-party relational database management systems (DBMSs), including market leaders Computer Associates International Inc., Garden City, N.Y.; Oracle Corp., Redwood City, Calif.; Sybase Inc., Everyville, Calif.; Informix Software Inc., Menlo Park, Calif.; and Novell Inc., Provo, Utah.

The database link, and cornerstone of data delivery within Information Warehouse, is the Distributed Relational Database Architecture. DRDA was first unveiled in 1990 as a key portion of the Common Communications Support (CCS) layer of SAA. DRDA enables access to distributed data across the four SAA relational DBMSs, and non-IBM databases that implement DRDA.

Kurt Siebert, vice president of strategic business alliances at Computer Associates, said, "Endorsement of DRDA will happen when DRDA becomes viable. And any product that CA acquires will, over time, be enabled with DRDA. We will follow the client's requirements."

Despite the impressive list of third-party vendors that have agreed to support DRDA, skeptics note that IBM's top computer rival, Digital Equipment Corp., Maynard, Mass., continues to look to the SQL Access Group for a standard relational DBMS link, charging that DRDA is proprietary. Meanwhile, the SQL Access Group, a vendor-sponsored standards group, has yet to convince IBM or Computer Associates to join.

For some observers, the perception that SAA's promise is still years away has changed, as IBM continues unveiling frameworks incorporating the architecture.

The promise of SAA is "maturing nicely," said Geoffrey Staples, a member of the Senior Technical Group at NIMS Associates Inc., located in Dallas.

Staples contended that SAA represents IBM's acceptance of the "open systems" concept, a move that represents a milestone in the computer industry. The SAA plan calls for an architecture that allows applications to run across four key IBM operating systems--OS/2, OS/400, MVS and VM--with links to others, including DOS/VSE and the IBM Unix implementation, AIX.

"SAA is providing movement into the new technology," Staples contended. "By allowing heterogeneous platforms, IBM is indicating that the market can no longer be dominated by the proprietary products of a single vendor."

Observers note that IBM has followed through on its promise to underscore the contributions of business partners to its series of SAA frameworks which, in addition to Information Warehouse, include System View, AD/Cycle and Office Vision.

IBM first outlined its SAA strategy for distributed data in October 1988. At the time, IBM identified four phases, or levels, of distributed databases. They are:

* Remote Request--the ability to make single SQL requests from a remote location.

* Remote Unit-of-Work (RUOW)--the ability to process transactions against a single remote database. (Each transaction is a set of interdependent SQL statements that, together, perform a piece of work; in other words, they commit together.)

* Distributed Unit-of-Work (DUOW)--the ability to process transactions against multiple remote databases. (This level of distribution requires a two-phase commitment control capability.)

* Distributed Request--the ability to process a single SQL statement that requires combining data from multiple distributed databases efficiently.

According to IBM, the DRDA architecture specifies how different relational DBMSs can communicate, facilitating access to data elsewhere in an enterprise. DRDA supports RUOW, but was first confined mostly to supporting links of like-to-like databases. With its list of nine DRDA supporters, disclosed in September (see box, page 49), IBM expanded DRDA to support RUOW on unlike databases.

Steve Knowles, connectivity product manager at Sybase, contended that most third-party relational DBMSs already support distributed transactions (DUOW) among like databases. "DRDA functionality is not new at this level," Knowles said. "But it does provide a good architecture for moving forward. IBM has done the right thing in focusing on protocols and architectures, rather than developing an application-level interface."

One of the products supporting DRDA is the new SQLGateway from Gupta Technologies, Menlo Park, Calif. SQLGateway is OS/2-based and can provide transparent and simultaneous access to SAA databases, including DB2, SQL/DS, AS/400 Database Manager and OS/2 EE Database Manager. Gupta said it will begin shipping SQLGateway by March 1992.

Support for IBM's DB2 and the distributed relational database technology is also coming from Compuware Corp., Farmington Hills, Mich., whose TransRelate Workbench and File-AID/DB2 2.1 data manipulation and testing tools are in beta test.

SAA backers contend that customer requirements are moving the industry to the client/server model of data processing. IBM's recent contention that it can provide RUOW between OS/2 and DB2 can permit OS/2-based programs to access data both from OS/2's Data Manager and the DB2 mainframe database. Meanwhile, IBM said the DB2 database can now be updated without having any update program running on the host. "Connectivity between OS/2 and DB2 is what the users wanted," said Linda Garcia-Rose, marketing manager for Candle Corp., in the New York City office.