The Windows NT market is full of powerful databases: Sybase, Oracle,
Microsoft, Informix, and IBM all have robust offerings. IBM? Like most of the IS
community, you probably associate Big Blue's DB2 database with mainframes and
the glass house rather than NT and the Internet. But this is not your father's
DB2. IBM includes many features in DB2 for NT that the other big names
incorporate into their products and even goes a step further to include support
for multimedia data types (for a quick overview of DB2's features, see the
sidebar, "DB2 for NT at a Glance," page 91). If what you need is
guaranteed scaleability, support for multimedia objects now (not later), or the
ability to leverage existing DB2 skills in your IS shop, then DB2 provides a
good alternative to Microsoft's SQL Server in a back office environment. If you
need handholding with database tuning or management, SQL Server's administration
tools make it a better choice.
Windows NT Integration
Although IBM's OS/2 Warp Server competes head to head with NT Server, the
company tuned DB2 for NT, adopting NT's threaded model and mapping it onto the
DB2 Common Server model. "That gives you the ability to scale up,"
explained Rakesh Golenka, product manager for DB2 for NT at IBM's Toronto,
Canada, facility. "You can use multiple processors in a symmetrical
multiprocessing (SMP) configuration to provide better performance."
DB2 also takes advantage of NT's native I/O. You can, for instance, assign
DB2 storage disks to do bulk reads or bulk writes without invoking DB2 to do so,
Golenka said. IBM is trying to clean up its image for releasing
somewhat-compatible products by letting DB2 take full advantage of the NT API
for tape backup and the NT Registry to show information about the product.
DB2 for NT comes with a performance monitor and integrates with NT's Event
Log and Perfmon. "We use APIs to pass DB2 performance data to the Windows
NT Performance Monitor," Golenka said. Because DB2 writes to Perfmon's
APIs, DBAs can then use NT's Perfmon to track DB2 performance in the event of a
problem. This approach is not as intuitive as SQL Server's, which provides a
graphical Performance Monitor interface that's easier for users with less
experience to use. DB2 also uses NT's domain services to manage group access to
its databases.
IBM made sure DB2 for NT conforms to the Microsoft BackOffice logo server
requirements, but not the client requirements. For information about these
requirements, see "BackOffice Logo Server Requirements," page 91.
Common Code Base
Despite IBM's efforts to harmonize DB2 with NT, one of DB2's strengths is
its support for multiple heterogeneous platforms with a common interface and
functionality. "The key differentiator between everybody [else] and SQL
Server for NT is portability," said Herb Edelstein, president of Two Crows,
a database and data mining consultancy in Potomac, Maryland. "Microsoft
believes as long as it runs on NT, that's the definition of an open system. For
enterprise computing, UNIX is going to remain more important than NT for quite a
while."
DB2 includes multiplatform support for Windows 95 (as a single-user
version), NT, OS/2, various flavors of UNIX, OS/400, and MVS. The MVS and OS/400
versions differ from the others in the way the commands operate, but the NT,
UNIX, and OS/2 products share a common code base, DB2 Common Server, which lives
on UNIX in C++. "Ninety percent of the code is common and 10 percent maps
onto the software platform," IBM's Golenka said. DB2's interfaces, data
schema, triggers, and row-level locking are all similar from platform to
platform.
IBM has taken some flak for the differences among DB2's various versions.
Analysts agree that the current incarnation of DB2 is more consistent than
previous versions, but no one seems to believe the Common Server platforms will
ever reconcile with the AS/400 and MVS versions.
For IBM, the common code approach means IBM has to develop only once for
three platforms. For developers, this approach means application scaleability:
DB2's reach meets NT's scaleability at a four- and eight-way SMP configurations.
IBM's legacy of corporate support--reliability, availability, and
serviceability-- and DB2's stability (DB2 is more than 13 years old) help make
DB2 attractive to shops that already have DB2. In such shops, programmers can
start to work with the NT version without retraining.
DB2 will also appeal to shops with experienced DBAs, shops that already have
DB2 on other platforms, and shops that want a smaller version of the big, robust
databases DB2 is known for. "IBM has a very strong relationship with IS
departments," said Kusnetzky, far better than Microsoft does. "DB2 is
a strong contender for IS departments selecting NT as a platform."