"Swiss Army Knife" Servers
SQL DBMS vendors such as IBM, Microsoft, Oracle and Sybase
have been in competition since the 1980s. The competition benefits the SQL
community because vendors and open source initiatives continue
to add new capabilities with each new server release.
| Microsoft enhanced SQL Server for
OLAP by adding cube queries and multidimensional expressions (MDX) in Transact-SQL
queries. IBM, Oracle, Sybase and others embraced object-relational technology and
Java
in the database. Microsoft added the Common Language Runtime (CLR) to SQL
Server 2005, much as other DBMS vendors integrated the Java Runtime Environment
(JRE) into their servers. |
|
With the emergence of XML, there was a growing expectation that SQL servers would support both data processing and document processing. Open source
projects developed tools for XML and web services development, but open source database management systems (DBMS) lagged behind commercial products in XML integration.
The major SQL vendors, including IBM, Microsoft and Oracle, implemented the SQL:2003 XML data type and query processing with XPath and XQuery.
Server Plug-Ins and Object-Relational Technology
IBM, Informix, Oracle and Sybase adopted object-relational
technology to augment traditional types such as numbers and characters. The traditional SQL server
evolved into extensible platforms with an architecture that accepts plug-ins. Servers
plug-ins provide user-defined types and new access methods. As a result, a
database is not longer simply a passive data container. Modern databases contain
logic. For an overview of this concept, read "New Servers,
New Architectures, and Logic in the Database". It explains
universal databases, extenders, and logic in the database. For a
look at this subject from a Java perspective, read "Java
in the Database, Objects in the Middle Tier".
| The Server Watch follows emerging database technologies
and discusses server-side programming technologies. These technologies include
IBM
DB2
Extenders, SQL Server Extended Stored Procedures, and IBM Informix
DataBlades. Check here from time to time for updates
about server capabilities and server programming. The extensible
architecture and object-relational technology have enabled SQL servers to
operate with Java-enabled and XML-enabled
databases. |
|
Java-Enabled Databases
Several major SQL providers have embraced Java in the database as a
preferred technology for creating database plug-ins. Installing Java classes in
databases adds types and behavior. Oracle JServer and IBM DB2 UDB use the Java
Runtime Environment to execute Java database plug-ins. A database containing
Java plug-ins is known as a Java-enabled database.
SQL providers who offer Java-enabled databases support the use
of JDBC and SQLJ in database plug-ins. Servers that operate on Java-enabled databases
use an internal JDBC driver for executing server-side JDBC programs. Programmers
writing Java classes to plug into a database can use dynamic SQL (JDBC) or static SQL (SQLJ).
"Java Objects in the
FirstSQL/J Database" by Lee Fesperman explains how to program with Java objects
and FirstSQL/J. It includes a money class example.
"Java
in the Database" (Java Pro, March 1999) explains how IBM,
Oracle, Sybase, Cloudscape, and Informix
database management systems support embedded Java. It explains SQLJ, and programming Java classes to
install in SQL databases. The example source code uses JDBC to do a SOUNDEX search of a Sybase
Adaptive Server database.
"Java,
JDBC, Stored Procedures, and Server-Mania" discusses IBM
Informix
Dynamic Server and plug-ins such as the Web DataBlade (Web Integration Option). It
explains the use of stored procedures in JDBC programs and includes downloadable Java
source code.
"Understanding Java-Enabled Databases and
Adaptive Servers" explains how to program Java classes to
install in databases. It includes example code for doing JDBC queries and Metaphone
phonetic searches with Sybase Adaptive Server. An earlier
version appeared in the Database Developer column of Web Techniques.
This article in Dr.
Dobb's Journal (August 1999) discussed techniques for extending IBM DB2
Universal Database (UDB).
Extenders,
UDFs, and Stored Procedures
Universal databases for rich data types
Database
managers have long been used as building blocks for online transaction
processing, decision support, and operational systems. Traditional SQL
database management systems (DBMS) have done well in managing tables of
numbers and characters, but the database development landscape is changing,
and influences such as object-oriented programming and the World Wide Web
have raised expectations. Now both users and developers expect to store
behavior and use richer data types.
Clearly, the emerging generation of feature-rich applications require
multimedia, geospatial data, and types that are more complex than
traditional SQL rows and columns. Consequently, developers require
sophisticated database managers for complex data, User-Defined Functions (UDFs),
and User-Defined Types (UDTs). The need for richer types and custom
behaviors is a primary reason developers are moving to universal databases
-- that is, tools for storing all types of data in a database -- that have
object-relational characteristics. Universal databases also store behavior
such as methods, functions, triggers, constraints, and procedures.
DB2
Universal Database
When
traditional SQL DBMSs evolved into Object-Relational DBMSs (ORDBMS), IBM was
an early supplier of object-relational technology. IBM consolidated several
DBMS tools to produce its DB2 Universal Database (UDB). UDB supports active
databases that contain rules and logic, making it possible for you to rely
on the database manager to enforce rules about data. UDB offers an
open-ended architecture for developing custom types and behaviors, and lets
you create both distinct and structured UDTs.
"Tool
Suites, MDX and SQLJ" discusses embedded SQL for Java.
Use an object-relational database to store a complete Web
site? How? Read "Dynamic Servers and Web Pages in a
Database" in the December 1998 issue of Web Techniques. It discusses Informix Dynamic Server's Web Integration
Option, Data Director for Web, DataBlades, and dynamic generation of HTML pages from Web
sites stored in Informix databases.
"IBM
DB2 Goes from Glass House to Global Village" (Internet Computing, May
1998) describes IBM DB2 Universal Database, DB2
Extenders, and content-based queries (QBIC).
"APIs for Universal Database Programming"
(Web
Techniques, August 1998) explains IBM DB2 programming using
ESQL, CLI, administrative APIs, DB2 Extenders, Java UDFs, and Java Stored Procedures.
"Sybase Puts Java
on Enterprise Pedestal" (Internet Computing, March, 1998) describes Sybase Adaptive Component
Architecture, Java in the database, jConnect, and enterprise Java developer tools.
"XA, Java Ease Distributed TP"
(PC Week, December 1998) discusses Java extensions for distributed
transaction processing.
From the Database Developer column by Ken North (Dr.
Dobb's Sourcebook,
September 1997)
Java in
the Database, Objects in the Middle Tier
Database developers have numerous options for
laying out the architecture of an application, so many that we often face a
classic decision about where to put logic. Sometimes the best solution to
a major problem is to apply a small bit of discrete logic at the right place
and time. During the Apollo program, the assignment of improving task
termination and error recovery for NASA's Goddard Real-Time System (GRTS) fell
into my lap. GRTS was part of the network that tracked lunar spacecraft. The
software ran on IBM mainframes as mission-critical, real-time extensions to
IBM's OS/360 operating system. GRTS used a main task/subtask architecture and
executed in an unprotected address space. My challenge was to keep problems such
as disk I/O errors during subtask loading from bringing down the system. No one
wanted to say "Houston, patch around us," or worse yet, "Apollo,
we have a problem!"
The error-handling solution involved the installation of a transient SVC
(Supervisor Call), a discrete bit of logic in a small module that the operating
system loaded when needed. Today, operating systems such as UNIX and Windows NT
routinely use a similar technique in the form of loadable device drivers. What
was once true about operating systems is now true about database software --
adding extensions can solve problems or supplement core functionality. Many
early DBMS products were closed systems that supported only a query language
interface.
Oracle, Microsoft and IBM provide extensions for XML processing with their
database servers. These servers can store and retrieve XML data as entire
documents (native XML) or map documents to multiple columns in tables
(shredding).
XML-enabled database servers can execute SQL queries that return XML
documents. They support the use of XPath expressions in queries and Extensible
Stylesheet Language (XSL) transformations.
Using SQL as a Conceptual Hierarchical Data Modeling and Processing Language for
XML
What makes this paper of significant importance to the SQL/XML industry is it proves how standard
SQL can perform full multi-leg hierarchical processing. It explains how the relational Cartesian processing engine automatically and inherently performs Lowest Common Ancestor (LCA) logic
that's required to perform hierarchical processing. This is original material
from Michael David.
"Center
of the Universe" (Intelligent Enterprise, May 2003) discusses
how IBM, Microsoft and Oracle are marrying SQL, XML, web services and grid
computing in their race to offer the best database product.
"Text Indexing, XML Searches, And Other Database Tricks"
(Web Techniques, February 2000) discusses database capabilities for
indexing and searching XML documents.
"Oracle:
Powered by XML and Java " (XML, Winter 1999/2000) discusses
support for XML in Oracle 8i and Oracle's tool set.
"Center
of the Universe" (Intelligent Enterprise, May 2003) discusses
integrated XML messaging, XQuery and XML schema support provided by IBM,
Microsoft and Oracle.
"XQuery and SQL: Vive la Différence" (DB2
magazine) discusses XQuery, SQL and the XQuery API for Java.
"Schema,
query: Is it database or XML?" (searchDatabase, February 2001)
discusses the XML Query Language.
" XML and Databases: Too Much Confusion" (XML-Journal) discusses XML/SQL integration.
Download
Volume 1, Number 2.
Databases and XML: Different
Worlds? is an
interview with author Akmal Chaudhri. Requires Real Video or Real One player.
