<?xml version="1.0" encoding="ISO-8859-1"?>
<!--
 -  
 -  This file is part of the OpenLink Software Virtuoso Open-Source (VOS)
 -  project.
 -  
 -  Copyright (C) 1998-2018 OpenLink Software
 -  
 -  This project is free software; you can redistribute it and/or modify it
 -  under the terms of the GNU General Public License as published by the
 -  Free Software Foundation; only version 2 of the License, dated June 1991.
 -  
 -  This program is distributed in the hope that it will be useful, but
 -  WITHOUT ANY WARRANTY; without even the implied warranty of
 -  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 -  General Public License for more details.
 -  
 -  You should have received a copy of the GNU General Public License along
 -  with this program; if not, write to the Free Software Foundation, Inc.,
 -  51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 -  
 -  
-->
<chapter label="virtwhitepaper.xml" id="virtwhitepaper">
	<title>White Paper</title>
	<abstract>
<para>The OpenLink Virtuoso white paper.  Universal Data Access Without Boundaries&#153;</para>

<para>Prepared By: Kingsley Idehen, President &amp; CEO OpenLink Software</para>
</abstract>
	<!-- ======================================== -->
	<sect1 id="vwpneed4vdb">
		<title>The Need For Virtual Database Engines</title>
		<sect2 id="vwpsitanal">
			<title>Situation Analysis</title>
			<para>As computer hardware, network protocols,
    database engines, applications, application servers, and desktop productivity tools,
    proliferate the enterprise, integration of disparate applications from disparate vendors
    is becoming an all too common problem. </para>
			<para>Add the emergence of standards based Distributed Computing galvanized by the Internet
    infrastructure and associated Internet protocols to this picture, and the need for
    Integration is even higher.</para>
			<para>Increasing the industry at large is looking to a new technology deliverable known as
    Universal Data Access Middleware to address these systems integration pains. </para>
			<para>&quot;With Universal Data Access (UDA), customers receive all of the benefits of a
    high-level and consistent Application Programming Interface (API) that abstracts all the
    database complexities while providing a capability that can be specified, controlled, and
    managed on its own to optimize the near universal need of programs for data access&quot;. </para>
			<para>
				<emphasis>Source IDC, 1998 Middleware Markets &amp; Trends </emphasis>
			</para>
			<para>At OpenLink Software, it is our opinion that a new genre of UDA middleware called the
    &quot;Virtual Database&quot;, is set to emerge as the dominant UDA middleware solution for
    addressing the integration challenges as they exist today, and tomorrow. This new UDA
    middleware format plays the role of a Universal Data Access manager, fusing traditional
    database functionality and traditional data access middleware functionality into a single
    independent packaged software solution.</para>
		</sect2>
		<!-- ###################################################### -->
		<sect2 id="vdbedef">
			<title>Virtual Database Engines Defined</title>
			<para>A Virtual Database (VDB) Engine is a UDA middleware
    format that transparently brings local and or remote heterogeneous databases together
    using logical database references called Data Source Names (DSN&apos;s). A VDB Engine exposes
    Metadata and Data held within these heterogeneous DSN&apos;s to clients applications and
    services homogeneously. </para>
			<para>VDB Engines presume the existence of a number of Database Engines and Data Access
    Drivers provided by a variety of database vendors within an organization. VDB Engines
    provide transparent access to these heterogeneous databases via DSN&apos;s associated with the
    relevant data access drivers without exposing end-users or developers to the intricacies
    of heterogeneous data access.</para>
		</sect2>
		<sect2 id="dsns">
			<title>Data Source Names (DSN&apos;s)</title>
			<para>A Data Source Name is a logical reference that
    exposes database to standards compliant or native data access drivers. DSN&apos;s provide a
    flexible naming and binding service for database driven applications developers and
    end-users alike. Applications no longer need to be inextricably linked to specific
    database names or specific database engines.</para>
		</sect2>
		<!-- ###################################################### -->
		<figure id="imagewp01" float="1">
			<title>Distributed Computing Infrastructure Incorporating A Virtual Database Engine</title>
			<graphic fileref="wpImage18.gif" width="782px" depth="539px"/>
		</figure>
	</sect1>
	<!-- ###################################################### -->
	<sect1 id="vwpfirstvdbps">
		<title>First Generation Virtual Database Products</title>
		<para>Although the strict VDB definition may be new,
    there are a number of products that have been around for a while that attempt to address
    VDB issues. The list of such products includes The Microsoft JET Engine, Borland Database
    Engine (BDE), and IBM DataJoiner.</para>
		<sect2 id="msjet">
			<title>Microsoft JET</title>
			<para>The Microsoft JET Engine lies at the heart of
    Microsoft Access, it is the piece of technology that allows you to link external and
    typically remote database tables into your local Access space via ODBC Data Sources. Once
    this link process has been completed, Access allows you to build Queries, Reports, Forms
    etc. using these external database tables as though they were Local Access tables. JET can
    also link to external tables hosted within desktop database engines via native interfaces.</para>
			<para>The Microsoft JET Engine services are exposed via Microsoft provided data access
    interfaces such as: DAO, ADO, and OLE-DB. These interfaces are integral parts of most
    Microsoft applications, thereby exposing the benefits of the JET VDB transparently.</para>
		</sect2>
		<sect2 id="borlandbde">
			<title>Borland Database Engine</title>
			<para>The Borland Database Engine (BDE) from Inprise
    like the Microsoft JET Engine also facilitates external table linkage via ODBC Data
    Sources. The BDE also lets you link to external database tables via native database
    interfaces and there is no restriction to desktop database engines when you adopt this
    approach.</para>
			<para>Although the BDE has a published set of APIs, it is predominantly used by Inprise
    applications in very much the same way JET is used by Microsoft applications.</para>
		</sect2>
		<sect2 id="ibmdj">
			<title>IBM DataJoiner</title>
			<para>DataJoiner from IBM provides the ability
    access heterogeneous data sources via IBM DB/2 Client Application Enablers. It does
    support ODBC and JDBC as client interfaces and makes use of Native or ODBC based data
    access for external Data I/O.</para>
		</sect2>
	</sect1>
	<!-- ###################################################### -->
	<sect1 id="vdbimpliss">
		<title>VDB Implementation Issues</title>
		<para>The essential components that affect the
    implementation of VDB Engines are, High-Level Data Access Interfaces, Low-Level Data
    Access Interfaces and Traditional Database Functionality.
</para>
		<sect2 id="hilevdai">
			<title>High-Level Data Access Interfaces</title>
			<para>A VDB Engine&apos;s capabilities are exposed via High
    Level Data Access interfaces. For the purpose of this document, a high level data access
    interface is an interface utilized predominantly by applications, as opposed to middleware
    developers for achieving application database independence. A high level data access
    interface sits atop Low-Level data access interfaces, providing an abstraction layer that
    serves to simplifying the process of database independent application development.</para>
			<para>A number of High Level Data Access standards exist today, the more prevalent being:</para>
			<simplelist>
				<member>
					<ulink url="http://www.microsoft.com/vbasic/techmat/whitepapers/ado20/">Data Access Objects (DAO)</ulink>
				</member>
				<member>
					<ulink url="http://www.microsoft.com/vbasic/techmat/whitepapers/ado20/">Remote Data Objects (RDO)</ulink>
				</member>
				<member>
					<ulink url="http://www.microsoft.com/data/ado/">ActiveX Data Objects (ADO)</ulink>
				</member>
				<member>
					<ulink url="http://www.microsoft.com/data/oledb/">OLE-DB</ulink>
				</member>
				<member>
					<ulink url="http://java.sun.com/products/java-blend/index.html">JavaBlend</ulink>
				</member>
				<member>
					<ulink url="http://java.sun.com/beans/infobus/index.html">InfoBus</ulink>
				</member>
			</simplelist>
			<para>It is important to note that low-level Data access interfaces such as ODBC, UDBC, JDBC
    and OLE-DB transparently serve the high-level interfaces mentioned in the section above.
    Thus, in most cases VDB vendors will treat ODBC, UDBC, JDBC, and OLE-DB as high-level
    interfaces by providing VDB data access drivers conforming to these standards as part of
    the VDB deliverable.</para>
		</sect2>
		<sect2 id="ibmdj">
			<title>Low-Level Data Access Interfaces</title>
			<para>A VDB Engine&apos;s data I/O occurs via
    low-level data access interfaces to underlying database engines or data sources. In recent
    times the Open Database Connectivity (<ulink url="http://www.microsoft.com/data/">ODBC</ulink>)
    API and the X/Open <ulink url="http://www.jcc.com/sql_stnd.html">SQL</ulink> Call Level Interface
    (CLI) have emerged as the dominant industry wide Low-Level Data Access Standards. OLE-DB
    from Microsoft is also emerging as a new low-level data access standard for relational and
    non-relational data in the Microsoft Component Object Model (COM) world. While JDBC is
    emerging like wise as the low-level data access standard for the burgeoning Java world.</para>
			<para>A VDB may also be a Native Database Interface Client, making use of database engine
    vendor provided data access interfaces. Native interfaces are based upon Embedded SQL, an
    older format Low-Level data access interface that preceded the X/Open SQL CLI. It is
    important to note that ODBC from Microsoft, JDBC from JavaSoft, and UDBC from OpenLink
    Software are all derived from the X/Open SQL CLI.</para>
		</sect2>
		<sect2 id="ibmdj">
			<title>Traditional Database Functionality</title>
			<para>The degree to which a VDB implements a traditional
    database engine&apos;s functionality has a direct bearing on the intrinsic value of a VDB
    engine. Traditional database functionality is extensive, but for the purposes of this
    document, a core set of functionality common to all commercial database engines has been
    assembled. The functionality list includes:</para>
			<formalpara>
				<title>Query Language Support</title>
				<para>standard syntax for interrogating, manipulating,
    describing, and securing data contained within a database. Examples include the Structured
    Query Language (SQL) for relational databases and the Object Query Language (OQL) for
    Object and Object-Relational Databases.</para>
			</formalpara>
			<formalpara>
				<title>Query Processor</title>
				<para>the mechanism used by a database engine to convert Query
    Language Statements into actual data retrieval instructions. In addition, this database
    component is responsible for ensuring Query Language syntax conformance, Query Execution
    Plan Assembly and Query Fulfillment. </para>
			</formalpara>
			<formalpara>
				<title>Standard Data Types Support</title>
				<para>data contained within a database must be
    describable using standard data types e.g. Character, Number, Date, etc.</para>
			</formalpara>
			<formalpara>
				<title>VIEW Support</title>
				<para>pre constructed query statements stored within a database,
    for the purpose of query simplification, or content and structural security.</para>
			</formalpara>
			<formalpara>
				<title>Stored Procedure Support</title>
				<para>Stored Procedures facilitate the embedding of
    application programming logic within a database. Their pre-compiled nature enhances data
    access performance by reducing message hops between database servers and database clients.</para>
			</formalpara>
			<formalpara>
				<title>Scrollable Cursor Support</title>
				<para>the process by which the result of a database
    query (known as a result-set) is traversed. Traversal occurs in either direction,
    backwards or forwards, using result-set chunks (known as row-sets). Resultset scrolling
    occurs when database engines exchange data with database clients.</para>
			</formalpara>
			<formalpara>
				<title>Concurrency Control</title>
				<para>the process through which a database engine supports
    multiple sessions running concurrently, across multiple database users and database client
    applications without compromising underlying data integrity or introducing quantum
    increases in application response times.</para>
			</formalpara>
			<formalpara>
				<title>Transaction Support</title>
				<para>ensures that database instructions can be grouped into
    logical units of execution that are Atomic, Consistent, Isolated from the effect of other
    units of execution affecting the same underlying data, and Durable.</para>
			</formalpara>
			<formalpara>
				<title>Transaction Isolation</title>
				<para>describes the ability of a database engine to provide
    transaction process partitioning options called Isolation Levels, that offer different
    ways of managing the effects of multiple and concurrent transactions affecting the same
    underlying data.</para>
			</formalpara>
			<formalpara>
				<title>Distributed Transaction Support</title>
				<para>describes the ability to preserve
    transaction atomicity, consistency, integrity, and durability across database servers
    hosted on the same or different database server machines within a networked environment.
    This involves supporting transaction Commits and Rollbacks using a 2-phase commit
    protocol.</para>
			</formalpara>
			<formalpara>
				<title>User Definable Type Support</title>
				<para>this is how a database engine allows
    end-users extend its base functionality. This is achieved by providing interfaces that
    allow end-users create new ways in which a database engine&apos;s data is described and
    manipulated.</para>
			</formalpara>
			<formalpara>
				<title>Federated Database Support</title>
				<para>data access and manipulation across database
    servers resident on the same machine.</para>
			</formalpara>
			<formalpara>
				<title>Distributed Database Support</title>
				<para>data access, and manipulation across database
    servers resident on the different machines within a networked environment.</para>
			</formalpara>
			<formalpara>
				<title>Security</title>
				<para>the process by which data, and data transmission is protected
    using a combination of database and operating system privileges, roles and roles
    hierarchies. It also includes the ability of a database engine to protect data transmitted
    to its clients using data encryption.</para>
			</formalpara>
		</sect2>
	</sect1>
	<!-- ###################################################### -->
	<sect1 id="vdbcomponents">
		<title>Virtual Database Engine Components</title>
		<para>The prior section outlined the critical implementation
    issues that affect the development and implementation of VDB Engines. These issues form
    the basis around which a component based framework for depicting VDB architectures has
    been derived. </para>
		<para>The components that comprise a VDB Engine framework are as follows:</para>
		<sect2 id="dadrvr">
			<title>Data Access Drivers</title>
			<para>The VDB component that forms the entry point
    to the VDB Engine&apos;s services, these drivers may or may not conform to industry
    standards. Applications and Services that sit atop a VDB Engine must have their data
    access layers written to the same Application Programming Interfaces (APIs) implemented by
    the Data Access Drivers provided by a VDB engine.</para>
		</sect2>
		<sect2 id="secman">
			<title>Security Manager</title>
			<para>The VDB component that is responsible for
    protecting data and data transmission (using encryption) within the VDB Engine&apos;s
    domain. It is also responsible for managing Application, User, Group, Role and Domain
    privileges as they relate to the creation, manipulation and destruction of VDB data and
    metadata.</para>
		</sect2>
		<sect2 id="qrymangr">
			<title>Query Manager</title>
			<para>The VDB component that handles queries
    presented to it by the VDB Engine&apos;s data access drivers. It provides query syntax
    checking, query execution plan compilation, and query fulfillment services. A query
    processor is built in conformance to one or more query language specifications, the most
    notable being the Structured Query Language (SQL) for relational database engines, and the
    Object Query Language (OQL) for Object-Relational and Object Database engines.</para>
		</sect2>
		<sect2 id="metadmngr">
			<title>Meta Data Manager</title>
			<para>The VDB component that provides the Query
    Processor with information about the data entities from which the Query Processor&apos;s
    execution plan is derived. Metadata managers are also the components responsible for
    linking external data sources into the VDB domain and directing the Query Processor to the
    appropriate Data I/O manager. </para>
		</sect2>
		<sect2 id="tranmgr">
			<title>Transaction Manager</title>
			<para>The Transaction Manager component ensures that
    transactions are Atomic (clearly distinguishable units), Consistent (thereby preserving
    integrity of data), Isolated from the effect of other transactions, and Durable (such that
    the effects of committed transactions survive failure). The Transaction Manager ensures
    VDB Engines are capable of supporting Online Transaction Processing (OLTP) and Distributed
    Transaction oriented applications and services. Transaction Managers may be standards
    based implementing X/Open&apos;s XA Resource Manager Specifications. Distributed
    transaction support is implemented by using a two-phase commit protocol.</para>
		</sect2>
		<sect2 id="concmngr">
			<title>Concurrency Manager</title>
			<para>The VDB component that ensures client applications and
    services are capable of opening multiple concurrent sessions that execute data INSERTS,
    UPDATES and DELETIONS, without implicitly reducing application response times or
    compromising data integrity. Concurrency control is delivered in one of two formats,
    Optimistic or Pessimistic depending on the response times desired by VDB client
    applications or services.</para>
		</sect2>
		<sect2 id="localiomngr">
			<title>Local Data I/O Manager</title>
			<para>VDB Engine&apos;s that provide local data
    storage uses this component for reading and writing data to disk. This is how a VDB
    provides traditional database engine data storage services. </para>
		</sect2>
		<sect2 id="extiomngr">
			<title>External Data I/O Manager</title>
			<para>VDB component that handles data reads and
    writes to external data sources. The External Data I/O Manager be implemented using
    standard data access interfaces such as ODBC, JDBC, UDBC, OLE-DB or Native data source
    interfaces. </para>
		</sect2>
		<sect2 id="rplmgr">
			<title>Replication Manager</title>
			<para>Component that manages data migration and
    synchronization across two or more VDB servers within a distributed computing environment.
    This component acts as a data coordinator between the activities of Local Data I/O and
    External Data I/O Managers across VDB servers. The Replication Manager enables a VDB
    Engine offer automated bi-directional data, and metadata transformation services across
    heterogeneous data sources without end-user or developer intervention.</para>
			<figure id="imagewp02" float="1">
				<title>Virtual Database Engine Architecture &amp; Components</title>
				<graphic fileref="wpImage19.gif" width="563px" depth="468px"/>
			</figure>
			<!-- ###################################################### -->
		</sect2>
		<sect2 id="vdbimplappro">
			<title>VDB Implementation Approaches</title>
			<para>There are no golden VDB implementation specifications,
    but the implementation of a VDB has a direct impact the degree to which you realize
    desired value from the VDB concept as a whole. </para>
			<para>The VDB value proposition is simply stated as follows: </para>
			<para>&quot;To provide transparent access to heterogeneous data sources, independent of host
        operating system and underlying database engines &quot;.</para>
			<para>VDB implementations can be categorized as follows:</para>
			<table colsep="1" frame="all" rowsep="0" shortentry="0" tocentry="1" tabstyle="decimalstyle" orient="land" pgwide="0">
				<title>VDB Implementation Categories</title>
				<tgroup align="char" charoff="50" char="." cols="4">
					<colspec align="left" colnum="1" colsep="0" colwidth="20pc"/>
					<thead>
						<row>
							<entry/>
							<entry>VDB Data Access Interface</entry>
							<entry>VDB External Data I/O</entry>
							<entry>Traditional Database Functionality</entry>
						</row>
					</thead>
					<tbody>
						<row>
							<entry>Type 1</entry>
							<entry>Native</entry>
							<entry>Native</entry>
							<entry>Partial</entry>
						</row>
						<row>
							<entry>Type 2</entry>
							<entry>Native</entry>
							<entry>Native</entry>
							<entry>Full</entry>
						</row>
						<row>
							<entry>Type 3</entry>
							<entry>Native</entry>
							<entry>Standards Based</entry>
							<entry>Partial</entry>
						</row>
						<row>
							<entry>Type 4</entry>
							<entry>Native</entry>
							<entry>Standards Based</entry>
							<entry>Full</entry>
						</row>
						<row>
							<entry>Type 5</entry>
							<entry>Standards Based</entry>
							<entry>Native</entry>
							<entry>Partial</entry>
						</row>
						<row>
							<entry>Type 6</entry>
							<entry>Standards Based</entry>
							<entry>Native</entry>
							<entry>Full</entry>
						</row>
						<row>
							<entry>Type 7</entry>
							<entry>Standards Based</entry>
							<entry>Standards Based</entry>
							<entry>Partial</entry>
						</row>
						<row>
							<entry>Type 8</entry>
							<entry>Standards Based</entry>
							<entry>Standards Based</entry>
							<entry>Full</entry>
						</row>
						<row>
							<entry>Type 9</entry>
							<entry>Standards Based</entry>
							<entry>Standards Based or Native</entry>
							<entry>Partial</entry>
						</row>
						<row>
							<entry>Type 10</entry>
							<entry>Standards Based</entry>
							<entry>Standards Based or Native</entry>
							<entry>Full</entry>
						</row>
					</tbody>
				</tgroup>
			</table>
			<para>The sections that follow provide illustrations of the
    different VDB formats, depicting the components that provide the basis for the
    categorization used in the table above.</para>
			<!-- ###################################################### -->
			<sect3 id="t1vdbngin">
				<title>Type 1 VDB Engine</title>
				<para>This category of VDB exposes its services to clients via Native and Proprietary
    high-level data access interfaces. Data I/O is achieved via native, proprietary, and data
    source specific low-level data access interfaces. This category of VDB does not possess a
    complete set of traditional database engine components.</para>
				<figure id="imagewp03" float="1">
					<title>Type 1 VDB Engine Architecture</title>
					<graphic fileref="wpImage20.gif" width="596px" depth="494px"/>
				</figure>
			</sect3>
			<sect3 id="t2vdbngin">
				<title>Type 2 VDB Engine</title>
				<para>This category of VDB exposes its services to clients via Native and Proprietary
    high-level data access interfaces. External data I/O is achieved via native, proprietary,
    and data source specific low-level data access interfaces. This category of VDB possesses
    a complete set of traditional database engine components.</para>
				<!-- ###################################################### -->
				<figure id="imagewp04" float="1">
					<title>Type 2 VDB Engine Architecture</title>
					<graphic fileref="wpImage21.gif" width="597px" depth="494px"/>
				</figure>
			</sect3>
			<sect3 id="t3vdbngin">
				<title>Type 3 VDB Engine</title>
				<para>This category of VDB exposes its services to clients via Native and Proprietary
    high-level data access interfaces. Data I/O is achieved via Open, Standards based, and
    Database Independent low-level data access interfaces. This category of VDB does not
    possess a complete set of traditional database engine components.</para>
				<!-- ###################################################### -->
				<figure id="imagewp05" float="1">
					<title>Type 3 VDB Engine Architecture</title>
					<graphic fileref="wpImage22.gif" width="596px" depth="494px"/>
				</figure>
			</sect3>
			<sect3 id="t4vdbngin">
				<title>Type 4 VDB Engine</title>
				<para>This category of VDB exposes its services to clients via Native and Proprietary
    high-level data access interfaces. External data I/O is achieved via Open, Standards
    based, and Database Independent low-level data access interfaces. This category of VDB
    possesses a complete set of traditional database engine components.</para>
				<!-- ###################################################### -->
				<figure id="imagewp06" float="1">
					<title>Type 4 VDB Architecture</title>
					<graphic fileref="wpImage23.gif" width="574px" depth="468px"/>
				</figure>
			</sect3>
			<sect3 id="t5vdbngin">
				<title>Type 5 VDB Engine</title>
				<para>This category of VDB exposes its services to clients via open and standards based
    high-level data access Interfaces. Data I/O is achieved via native, proprietary, and data
    source specific low-level interfaces. This category of VDB does not possess a complete set
    of traditional database engine components.</para>
				<figure id="imagewp07" float="1">
					<title>Type 5 VDB Engine Architecture</title>
					<graphic fileref="wpImage24.gif" width="614px" depth="494px"/>
				</figure>
				<!-- ###################################################### -->
			</sect3>
			<sect3 id="t6vdbngin">
				<title>Type 6 VDB Engine</title>
				<para>This category of VDB exposes its services to clients via
    open, standards based, high and low-level Interfaces. External data I/O is achieved via
    native, proprietary, and data source specific low-level interfaces. This category of VDB
    possesses a complete set of traditional database engine components.</para>
				<figure id="imagewp08" float="1">
					<title>Type 6 - VDB Engine Architecture</title>
					<graphic fileref="wpImage25.gif" width="588px" depth="494px"/>
				</figure>
			</sect3>
			<sect3 id="t7vdbngin">
				<title>Type 7 VDB Engine</title>
				<para>This category of VDB exposes its services via open, standards based high-level data
    access interfaces. Data I/O is achieved via Open, Standards based, and Database
    Independent low-level data access interfaces. This category of VDB does not possess a
    complete set of traditional database engine components.</para>
				<figure id="imagewp09" float="1">
					<title>Type 7 VDB Engine Architecture</title>
					<graphic fileref="wpImage26.gif" width="614px" depth="494px"/>
				</figure>
				<!-- ###################################################### -->
			</sect3>
			<sect3 id="t8vdbngin">
				<title>Type 8 VDB Engine</title>
				<para>This category of VDB exposes its services via open,
    standards based, high and low-level interfaces. External data I/O is achieved via Open,
    Standards based, and Database Independent low-level data access interfaces. This category
    of VDB does possess a complete set of traditional database engine components.</para>
				<figure id="imagewp10" float="1">
					<title>Type 8 VDB Engine Architecture</title>
					<graphic fileref="wpImage27.gif" width="614px" depth="548px"/>
				</figure>
			</sect3>
			<sect3 id="t9vdbngin">
				<title>Type 9 VDB Engine</title>
				<para>This category of VDB exposes its services via Open, Standards based, high-level
    data access interfaces. Data I/O is achieved by using either Open, Standards based, and
    Database Independent low-level data access interfaces or Native, Proprietary, and Database
    Specific low-level data access interfaces. This category of VDB does not possess a
    complete set of traditional database engine components.</para>
				<figure id="imagewp11" float="1">
					<title>Type 9 VDB Architecture</title>
					<graphic fileref="wpImage28.gif" width="570px" depth="484px"/>
				</figure>
				<!-- ###################################################### -->
			</sect3>
			<sect3 id="t10vdbngin">
				<title>Type 10 VDB Engine</title>
				<para>This category of VDB exposes its services via Open,
    Standards based, high-level data access interfaces. External data I/O is achieved by using
    either Open, Standards based, and Database Independent low-level data access interfaces or
    Native, Proprietary, and Database Specific low-level data access interfaces. This category
    of VDB possesses a complete set of traditional database engine components.</para>
				<figure id="imagewp12" float="1">
					<title>Type 10 VDB Architecture</title>
					<graphic fileref="wpImage29.gif" width="613px" depth="494px"/>
				</figure>
			</sect3>
		</sect2>
	</sect1>
	<sect1 id="Vnxtgenvdb">
		<title>OpenLink Virtuoso&#153; - Next Generation Virtual Database Engine</title>
		<para>Virtuoso is a revolutionary, next generation,
    high-performance virtual database engine for the Distributed Computing Age. It is an
    essential universal data access middleware technology set to accelerate our advance
    towards the emerging Information Age.</para>
		<para>Virtuoso provides transparent access to your existing data sources, which are logical
    references to databases from different database vendors, exposed by data access drivers
    also provided by different vendors. </para>
		<para>Through a single connection, Virtuoso will simultaneously connect your ODBC, JDBC,
    UDBC, OLE-DB client applications and services to data within Oracle, Microsoft SQL Server,
    DB/2, Informix, Progress, CA-Ingres, Sybase, PostgreSQL, Solid, Velocis and other ODBC
    compliant database engines. </para>
		<para>Virtuoso provides the end-user or applications developer with a one application or
    development environment to many database engines relationship abstracting either party
    from the complexities of heterogeneous data access. </para>
		<para>Virtuoso allows end-users and application developers to retain a single data source or
    database focus, at the same time exposing either party to the benefits of heterogeneous
    data access, without introducing proportional increases in complexity. </para>
		<para>Virtuoso is a type 10 VDB Engine, exposing its services via standards based data access
    interfaces such as ODBC, JDBC, UDBC, and OLED-DB and performing external Data I/O occurs
    via ODBC, UDBC, or Native data access interfaces.</para>
		<!-- ###################################################### -->
		<sect2 id="dsngoals">
			<title>Design Goals</title>
			<para>Virtuoso has been developed with the following goals in mind:</para>
			<orderedlist>
				<listitem>
					<para>Operating System Independence - support for all main stream operating systems</para>
				</listitem>
				<listitem>
					<para>Small Memory Footprint - no more than 2MB of memory for basic operations</para>
				</listitem>
				<listitem>
					<para>Small Binary Distribution - maximum of 10MB of disk space for base product
        installation</para>
				</listitem>
				<listitem>
					<para>High-Performance - deliver performance levels required by enterprise-wide solutions</para>
				</listitem>
				<listitem>
					<para>Standards Based data I/O - use standard such as ODBC from Microsoft and UDBC from
        OpenLink Software for low-level data access</para>
				</listitem>
				<listitem>
					<para>Standards based Interfaces to services - expose Virtual Database functionality via
        ODBC, UDBC, JDBC, and OLE-DB data access drivers</para>
				</listitem>
				<listitem>
					<para>Web Based Configuration &amp; Management - a Web Browser as the standard
        administration and configuration interface</para>
				</listitem>
			</orderedlist>
		</sect2>
		<sect2 id="arch">
			<title>Architecture</title>
			<para>Virtuoso&apos;s VDB type 8 architecture is depicted below. </para>
			<figure id="imagewp13" float="1">
				<title>OpenLink Virtuoso&#153; VDB Architecture</title>
				<graphic fileref="wpImage30.gif" width="632px" depth="494px"/>
			</figure>
			<note>
				<title>Note:</title>
				<para>support for JDBC and OLE-DB based external data I/O is still being developed.</para>
			</note>
		</sect2>
		<!-- ###################################################### -->
		<sect2 id="virtcompon">
			<title>Virtuoso Components</title>
			<sect3 id="dataadrvs">
				<title>Data Access Drivers</title>
				<para>ODBC, JDBC, UDBC, and OLE-DB Drivers for Virtuoso are
    an integral part of the OpenLink Virtuoso&#153; product set. Client applications and
    services consume the virtual database services provided by Virtuoso using one or more of
    these drivers.</para>
				<para>The features of these drivers are listed below:</para>
				<itemizedlist mark="bullet">
					<listitem>
						<para>Blistering Performance</para>
					</listitem>
					<listitem>
						<para>ODBC Drivers are ODBC v2.5 compliant </para>
					</listitem>
					<listitem>
						<para>ODBC Drivers implement driver based Scrollable Cursors</para>
					</listitem>
					<listitem>
						<para>Drivers for JDBC are JDBC v1.02, v1.1, and v2.0 compliant </para>
					</listitem>
					<listitem>
						<para>Drivers for JDBC implement driver based Scrollable Cursors</para>
					</listitem>
					<listitem>
						<para>OLE-DB Data Providers are OLE-DB 2.0 compliant.</para>
					</listitem>
				</itemizedlist>
			</sect3>
			<sect3 id="vcsecman">
				<title>Security Manager</title>
				<para>Virtuoso&apos;s security features are listed below:</para>
				<itemizedlist mark="bullet">
					<listitem>
						<para>User Login and Password Verification</para>
					</listitem>
					<listitem>
						<para>Role definition and privilege control</para>
					</listitem>
					<listitem>
						<para>Table and Column Level Privilege control</para>
					</listitem>
					<listitem>
						<para>Logical &quot;Rules Based&quot; Security - enabling
        security to be devised around custom rules that derive security conditions from a
        combination user, client applications, client operating system, and network address
        parameters if required</para>
					</listitem>
					<listitem>
						<para>Data Encryption - data transmission between Virtuoso
        and its clients can be secured via encryption.</para>
					</listitem>
				</itemizedlist>
			</sect3>
			<sect3 id="vcqmgr">
				<title>Query Manager</title>
				<para>Virtuoso&apos;s query manager features are as follows: </para>
				<itemizedlist mark="bullet">
					<listitem>
						<para>Supports ANSI SQL 92</para>
					</listitem>
					<listitem>
						<para>Parallel Query processing - enabling parallel
        execution plan assembly, query execution, and query fulfillment. </para>
					</listitem>
					<listitem>
						<para>Asynchronous Operation - all activities occur
        asynchronous except for transaction commits and rollbacks which occur synchronously.</para>
					</listitem>
					<listitem>
						<para>Distributed Join Optimizer - enabling high-performance
        heterogeneous joins across disparate database engines. </para>
					</listitem>
					<listitem>
						<para>Scrollable Cursor Engine - facilitates scrollable cursor
        support across heterogeneous database engines. This mechanism allows the manipulation of
        ResultSet subsets call RowSets that span multiple data sources and database engines. This
        sophisticated featured reduces record fetch overhead by migrating chunks of data in
        parallel from external data sources into Virtuoso and then out again to client
        applications and services. Virtuoso supports Static, Keyset, Mixed, and Dynamic Cursors.</para>
					</listitem>
					<listitem>
						<para>Heterogeneous VIEWS support - enabling the development of
        logical data snapshots that transcend disparate database engines. These VIEWS aren&apos;t
        updatable</para>
					</listitem>
					<listitem>
						<para>Generic Stored Procedure Language - enables the
        development of stored procedures that allow application logic to be stored and implemented
        at the VDB level, these stored procedures can reference tables hosted in disparate
        database engines. Virtuoso Stored Procedures are sensitive to metadata changes that occur
        within externally linked tables.</para>
					</listitem>
				</itemizedlist>
			</sect3>
			<sect3 id="vcmetatdatamgr">
				<title>Metadata Manager</title>
				<para>The Virtuoso Metadata Manger acts as the repository of all Virtuoso&apos;s database
    objects, this includes Metadata from external tables linked into Virtuoso, Native Tables,
    Stored Procedures, Views, Object Privileges, Indexes, Referential Integrity constraints,
    and Database Statistics.</para>
				<para>The Metadata Manager does not affect any of the external tables linked into Virtuoso.
    Thus, an external object dropped by the Metadata Manager simply equates to a reference
    drop within Virtuoso as opposed to an actual object drop within an external database
    linked into Virtuoso.</para>
			</sect3>
			<sect3 id="vctransman">
				<title>Transaction Manager</title>
				<para>The Virtuoso transaction manager possesses the following capabilities:</para>
				<itemizedlist mark="bullet">
					<listitem>
						<para>Commits &amp; Rollbacks - Transactions are either fully completed or not at all,
        when dealing with externally linked tables this behavior is preserved, but not to the
        point of a full 2-phase commit, this functionality will be available is a subsequent
        product release</para>
					</listitem>
					<listitem>
						<para>Supports read-only transactions, which provide no lock overhead and add flexibility to
        the VDB transaction model.</para>
					</listitem>
					<listitem>
						<para>Before &amp; After Image Transaction Logging - Virtuoso maintains database state
        logs before and after transactions. Thus, in time of failure it is possible to Roll the
        database back to a prior state preceding VDB server initialization. Virtuoso also allows
        you to roll forward your database by committing all uncommitted transactions held in After
        Image transaction logs when recovering from system failure.</para>
					</listitem>
					<listitem>
						<para>Supports Dirty Read, Read Committed, Repeatable Read, and Serializable transaction
        isolation levels</para>
					</listitem>
				</itemizedlist>
			</sect3>
			<sect3 id="vcsecman">
				<title>Concurrency Manager</title>
				<para>The concurrency manager ensures that Virtuoso is capable of supporting multiple
    concurrent database sessions that execute data INSERTS, UPDATES and DELETIONS access
    without compromising data integrity or implicitly increasing application or service
    latency.</para>
				<para>The Virtuoso Concurrency Manager supports Optimistic and Pessimistic (Locking)
    concurrency. </para>
				<para>Database Rows, Pages, or Tables aren&apos;t locked when Optimistic concurrency is in
    use, rather UPDATES or DELETIONS are simply rejected on the bases of other user process
    modifying the same record(s) that you are about to UPDATE or DELETE. Optimistic
    concurrency presumes low record UPDATE and DELETE frequency.</para>
				<para>Pessimistic concurrency on the other hand presumes a high level frequency of record
    UPDATE and DELETION activity. The Virtuoso concurrency manager implements Page Level
    locking, and these locks have configurable timeout settings, which reduce the probability
    of record deadlock which inadvertently introduce application latency. </para>
				<para>Row level locking is currently in development.</para>
			</sect3>
			<sect3 id="vclocaliomgr">
				<title>Local Data I/O Manager</title>
				<para>Virtuoso posses full native database engine capabilities, the local I/O Manager is
    responsible for writing data to local storage when Virtuoso is being used as an Embedded
    Database Engine. This feature of Virtuoso enables it to serve Application Server solutions
    as an embedded database engine outside the corporate firewall, providing these solutions
    with local storage at the same time reducing workload on the corporate databases behind
    the company firewall. </para>
			</sect3>
			<sect3 id="vcextiomgr">
				<title>External Data I/O Manager</title>
				<para>Virtuoso reads and writes data to external database engines using ODBC or UDBC as
    its external data I/O interface (supported for JDBC and OLE-DB based I/O is also planned).
    </para>
				<para>ODBC support enables Virtuoso to link and manipulate data held in ODBC compliant
    database engines, implying any database with an ODBC driver is accessible from Virtuoso.</para>
				<para>UDBC support enables Virtuoso to be hosted on operating system where ODBC is not&apos;t
    supported, it also enables Virtuoso to communicate with external databases using their
    native interfaces.</para>
			</sect3>
			<sect3 id="vcreplman">
				<title>Data Replication Manager</title>
				<para>The Virtuoso Replication Manager enables the automatic synchronization of data
    across Virtuoso Servers within your computing infrastructure. The replication process is
    bi-directional and is capable of replicating data across externally linked tables. </para>
				<para>Synchronization of replicated databases is
    automatic should one of the database within a replica group encounter system failure. </para>
			</sect3>
			<sect3 id="vcconductor">
				<title>Virtuoso Conductor</title>
				<para>This is a HTML based Administrative console that provides a graphical user
    interface for attaching and detaching external tables associated with your Virtuoso
    database engine. It also includes configuration wizards and a query editor that enables
    intuitive configuration and testing of the ODBC and UDBC data sources names that you plan
    to use with Virtuoso.</para>
			</sect3>
		</sect2>
		<!-- ###################################################### -->
		<sect2 id="implissschklst">
			<title>Implementation Issues Checklist</title>
			<para>Key</para>
			<simplelist>
				<member>Implemented - I</member>
				<member>Partially Implemented - PI </member>
				<member>Planned - P</member>
			</simplelist>
			<table colsep="1" frame="all" rowsep="0" shortentry="0" tocentry="1" tabstyle="decimalstyle" orient="land" pgwide="0">
				<title>Implementation Checklist</title>
				<tgroup align="char" charoff="50" char="." cols="2">
					<colspec align="left" colnum="1" colsep="0" colwidth="20pc"/>
					<thead>
						<row>
							<entry>VDB Implementation Issue</entry>
							<entry>Status</entry>
						</row>
					</thead>
					<tbody>
						<row>
							<entry>ODBC, UDBC, JDBC, OLE-DB based interface to VDB</entry>
							<entry>I</entry>
						</row>
						<row>
							<entry>ODBC &amp; UDBC based external data I/O</entry>
							<entry>I</entry>
						</row>
						<row>
							<entry>JDBC based external data I/O</entry>
							<entry>P</entry>
						</row>
						<row>
							<entry>OLE-DB based external data I/O</entry>
							<entry>P</entry>
						</row>
						<row>
							<entry>SQL Support </entry>
							<entry>I</entry>
						</row>
						<row>
							<entry>OQL Support</entry>
							<entry>P</entry>
						</row>
						<row>
							<entry>Query Processor </entry>
							<entry>I</entry>
						</row>
						<row>
							<entry>Heterogeneous Scrollable Cursor Support </entry>
							<entry>I</entry>
						</row>
						<row>
							<entry>Standard Data Types Support </entry>
							<entry>I</entry>
						</row>
						<row>
							<entry>VIEW Support </entry>
							<entry>I</entry>
						</row>
						<row>
							<entry>Stored Procedure Support </entry>
							<entry>I</entry>
						</row>
						<row>
							<entry>Concurrency Control </entry>
							<entry>I</entry>
						</row>
						<row>
							<entry>Transaction Isolation </entry>
							<entry>I</entry>
						</row>
						<row>
							<entry>Distributed Transaction Support </entry>
							<entry>PI</entry>
						</row>
						<row>
							<entry>User Definable Type Support </entry>
							<entry>I</entry>
						</row>
						<row>
							<entry>Federated Database Support </entry>
							<entry>I</entry>
						</row>
						<row>
							<entry>Distributed Database Support </entry>
							<entry>I</entry>
						</row>
						<row>
							<entry>Security </entry>
							<entry>I</entry>
						</row>
						<row>
							<entry>Replication Manager</entry>
							<entry>PI</entry>
						</row>
					</tbody>
				</tgroup>
			</table>
		</sect2>
		<!-- ###################################################### -->
		<sect2 id="featurebenanaly">
			<title>Feature &amp; Benefits Analysis (Virtual Database Functionality)</title>
			<table colsep="1" frame="all" rowsep="0" shortentry="0" tocentry="1" tabstyle="decimalstyle" orient="land" pgwide="0">
				<title>VDB Implementation Categories</title>
				<tgroup align="char" charoff="50" char="." cols="2">
					<colspec align="left" colnum="1" colsep="0" colwidth="20pc"/>
					<thead>
						<row>
							<entry>Feature</entry>
							<entry>Benefit</entry>
						</row>
					</thead>
					<tbody>
						<row>
							<entry>Transparent concurrent access
        to heterogeneous data sources and backend database engines.</entry>
							<entry>Cost effective mechanism for
        harnessing information from your existing databases and data sources in real-time.</entry>
						</row>
						<row>
							<entry>ODBC, JDBC, UDBC, and OLE-DB
        Driver availability.</entry>
							<entry>Provides exposure of virtual
        database services to the plethora of commercial ODBC, JDBC, UDBC, and OLE-DB based
        solutions currently in existence.</entry>
						</row>
						<row>
							<entry>ODBC, UDBC, or Native external
        Data I/O.</entry>
							<entry>Freedom to Mix &amp; Match the
        best combination of database engines and data access types for your organization</entry>
						</row>
						<row>
							<entry>Cross platform support
        (95/98/NT, Linux, Solaris, HP-UX, AIX, Digital UNIX, IRIX, SCO Unix, SCO Unixware, DG_UX,
        Dynix/PTX, BSDI, with VMS, MacOS, OS2, OS400, OS390 planned).</entry>
							<entry>Freedom to Mix &amp; Match the
        best combination of Application and Database server operating systems for your
        organization.</entry>
						</row>
						<row>
							<entry>Multiple database and ODBC data
        source name support:
	Virtuoso Native DBMS Server, Oracle(6/7/8), MS SQL
        Server(4/6.x/7.x), Informix(4/5/6/7), Progress (6/7/8/9), CA-Ingres (6.4), CA-OpenIngres
        (1.1/2.x), DB2 (2.12 &amp; 5.x), Sybase SQL Server (4.x/10.x/11.x), PostgreSQL, Solid,
        Velocis, and third party ODBC Drivers.</entry>
							<entry>Sustains or bolsters database
        independence within your organization.  This also ensures that new database driven
        technologies are usable with your existing database engines and data sources, thereby
        preserving database investments made in prior years.</entry>
						</row>
						<row>
							<entry>Multi Threaded Virtual Database
        Server.</entry>
							<entry>Parallel execution of data
        access instructions with minimal system overhead resulting in high-performance data
        throughput even when concurrent user counts are high.</entry>
						</row>
						<row>
							<entry>Asynchronous Data I/O.</entry>
							<entry>All data I/O except transaction
        commits and rollbacks are Asynchronous. Thus, reducing the probability of data I/O blocks
        that increase VDB server latency. </entry>
						</row>
						<row>
							<entry>Scrollable Cursors Support.</entry>
							<entry>Enables the use of High-Level
        data access interfaces such as RDO, ADO, OLE-DB, JDBC 2.0 against your existing databases
        and data sources. </entry>
						</row>
						<row>
							<entry>Sophisticated Concurrency
        Control.</entry>
							<entry>Provides scalability to your
        VDB based solutions.</entry>
						</row>
						<row>
							<entry>Stored Procedure Support.</entry>
							<entry>You can develop database
        independent stored procedures that can traverse all the databases in your organization
        using common stored procedure language.</entry>
						</row>
						<row>
							<entry>Sophisticated rules based
        security.</entry>
							<entry>You can control user
        privileges, define roles, and generally tighten security by adopting a &quot;Rule
        Book&quot; approach. This allows your security infrastructure be both logical and physical
        in nature, and driven by rules that you define. </entry>
						</row>
						<row>
							<entry>Centralized or Decentralized
        infrastructure management via Web Browser</entry>
							<entry>You can manage one or more
        geographically dispersed Virtuoso Servers from a single location or multiple locations
        through your Web Browser.  Zero Admin solution.</entry>
						</row>
						<row>
							<entry>Bi-Directional Heterogeneous
        Replication</entry>
							<entry>Allows numerous Virtuoso and
        non-Virtuoso database tables to be kept in sync throughout your distributed computing
        infrastructure without user intervention.  Reduces the cost typically associated with
        data transformation and migration. It also enables the development of sophisticated data
        caching for store-and-forward solutions. </entry>
						</row>
						<row>
							<entry>Full Relational and
        Object-Relational Database functionality</entry>
							<entry>Flexibility to build database
        solutions using relational or object-relational models.  Future proofs your applications
        development at the data access level.</entry>
						</row>
						<row>
							<entry>Small footprint </entry>
							<entry>Can operate within 2MB of RAM
        and consumes no more than 10MB of disk space for entire product installation.  This makes
        Virtuoso embeddable with solutions that are hosted on devices that have minimal memory and
        persistent storage capacity.</entry>
						</row>
					</tbody>
				</tgroup>
			</table>
		</sect2>
		<!-- ###################################################### -->
		<sect2 id="prodpack">
			<title>Product Packaging</title>
			<para>Virtuoso is available in 3 distinct product formats: </para>
			<itemizedlist mark="bullet">
				<listitem>
					<para>OpenLink Virtuoso&#153; Lite Edition</para>
				</listitem>
				<listitem>
					<para>OpenLink Virtuoso&#153; Workgroup Edition</para>
				</listitem>
				<listitem>
					<para>OpenLink Virtuoso&#153; Enterprise Edition</para>
				</listitem>
			</itemizedlist>
			<sect3 id="oplvirtlite">
				<title>OpenLink Virtuoso&#153; Lite Edition</title>
				<para>This is an entry-level product comprising the following components: </para>
				<itemizedlist mark="bullet">
					<listitem>
						<para>HTML based Interactive ODBC compliant Query Console</para>
					</listitem>
					<listitem>
						<para>Virtual Database Server </para>
					</listitem>
					<listitem>
						<para>Virtuoso Conductor - HTML based remote database management console</para>
					</listitem>
					<listitem>
						<para>OpenLink Virtuoso&#153; Single Tier ODBC &amp; UDBC Drivers </para>
					</listitem>
					<listitem>
						<para>OpenLink Virtuoso&#153; Type 4 Drivers for JDBC.</para>
					</listitem>
					<listitem>
						<para>Lightweight Thread Manager.</para>
					</listitem>
				</itemizedlist>
				<para>OpenLink Virtuoso&#153; Lite presumes the existence of ODBC or UDBC drivers within your
    existing IS infrastructure. It only includes ODBC and JDBC drivers for accessing the
    Virtual Database Server. It is important to note that prior to using Virtuoso, you must
    install and configure database specific network communications software and ODBC drivers
    provided by each of the database vendors whose products you will be exposing to Virtuoso.</para>
				<para>Examples of such database vendor provided products include: Oracle SQL*Net, Oracle
    Net8, Informix I-Connect, Ingres NET, Microsoft NETLIB, Sybase Open Client, Progress
    Client Networking, DB2 client enablers etc. Each of these products typically includes a
    free ODBC Driver.</para>
				<para>This product set supports the following operating systems:</para>
				<para>Windows 95/98/NT, Linux, Solaris (Sparc &amp; x86), AIX, HP-UX, IRIX, Dynix/PTX, DG-UX,
    Digital UNIX. MacOS, OS/2, and VMS ports are planned.</para>
			</sect3>
			<sect3 id="oplvirtwg">
				<title>OpenLink Virtuoso&#153; Workgroup Edition</title>
				<para>This is a departmental or small Internet/Intranet/Extranet server solution
    comprising the following components: </para>
				<itemizedlist mark="bullet">
					<listitem>
						<para>HTML based Interactive ODBC compliant Query Console</para>
					</listitem>
					<listitem>
						<para>Virtual Database Server </para>
					</listitem>
					<listitem>
						<para>Virtuoso Conductor - HTML based remote database management console</para>
					</listitem>
					<listitem>
						<para>OpenLink Virtuoso&#153; Single Tier ODBC &amp; UDBC Drivers </para>
					</listitem>
					<listitem>
						<para>OpenLink Virtuoso&#153; Type 1, 2, and 4 Drivers for JDBC.</para>
					</listitem>
					<listitem>
						<para>OpenLink Data Access Driver Suite (Lite Edition) supporting: Oracle, Microsoft SQL
        Server, Informix, Sybase, CA-Ingres, Progress, DB2, PostgreSQL, Velocis, and Solid</para>
					</listitem>
					<listitem>
						<para>Lightweight Thread Manager.</para>
					</listitem>
				</itemizedlist>
				<para>OpenLink Virtuoso&#153; Workgroup Edition includes OpenLink Software&apos;s
    high-performance Single Tier ODBC &amp; JDBC Drivers (a.k.a. OpenLink Lite). These drivers
    enable you to expose your existing database engines to Virtuoso right out of the box. It
    is important to note that prior to using Virtuoso, you must install and configure database
    specific network communications software and ODBC drivers provided by each of the database
    vendors whose products you will be exposing to Virtuoso.</para>
				<para>Examples of such database vendor provided products include: Oracle SQL*Net, Oracle
    Net8, Informix I-Connect, Ingres NET, Microsoft NETLIB, Sybase Open Client, Progress
    Client Networking, DB2 client enablers etc. Each of these products typically includes a
    free ODBC Driver.</para>
				<para>This product set supports the following operating systems:</para>
				<para>Windows NT, Linux, Solaris (Sparc &amp; x86), AIX, HP-UX, IRIX, Dynix/PTX, DG-UX,
    Digital UNIX. MacOS, OS/2, and VMS ports are planned.</para>
			</sect3>
			<sect3 id="oplvirtenterprise">
				<title>OpenLink Virtuoso&#153; Enterprise Edition</title>
				<para>This is an enterprise wide or large Internet/Intranet/Extranet server solution comprising
    the following components:</para>
				<itemizedlist mark="bullet">
					<listitem>
						<para>HTML based Interactive ODBC compliant Query Console</para>
					</listitem>
					<listitem>
						<para>Virtual Database Server - Implemented as an OpenLink Request Broker service</para>
					</listitem>
					<listitem>
						<para>Virtuoso Conductor - HTML based remote database management console</para>
					</listitem>
					<listitem>
						<para>OpenLink Virtuoso&#153; Multi-Tier ODBC &amp; UDBC Drivers </para>
					</listitem>
					<listitem>
						<para>OpenLink Virtuoso&#153; Type 1,2,3 &amp; 4 Drivers for JDBC</para>
					</listitem>
					<listitem>
						<para>OpenLink Data Access Drivers Suite (Multi-Tier Edition) supporting: Oracle, Microsoft
        SQL Server, Informix, Sybase, CA-Ingres, Progress, DB2, PostgreSQL, Velocis, Solid, and 3rd
        Party ODBC Drivers</para>
					</listitem>
					<listitem>
						<para>Heavyweight POSIX or Native Thread Manager.</para>
					</listitem>
				</itemizedlist>
				<para>OpenLink Virtuoso&#153; Enterprise Edition includes OpenLink Software&apos;s
    high-performance Multi-Tier ODBC &amp; JDBC Drivers. These drivers enable you to expose
    your existing database engines to Virtuoso right out of the box, without inherent
    dependencies on database vendor provided network software for remote database connections.
    </para>
				<para>Examples of such database vendor provided products include: Oracle SQL*Net, Oracle
    Net8, Informix I-Connect, Ingres NET, Microsoft NETLIB, Sybase Open Client, Progress
    Client Networking, DB2 client enablers etc.</para>
				<para>This product set supports the following operating systems:</para>
				<para>Windows NT, Linux, Solaris (Sparc &amp; x86), AIX, HP-UX, IRIX, Dynix/PTX, DG-UX,
    Digital UNIX. MacOS, OS/2, and VMS ports are planned.</para>
			</sect3>
		</sect2>
		<sect2 id="galvanizer">
			<title>Galvanizing Your Enterprise with OpenLink Virtuoso&#153;</title>
			<para>Virtuoso enables you to maximize the benefits
    of new distributed computing technologies and paradigms with minimum disruption, if any,
    to your existing computing infrastructure. The situation examples in the sections that
    follow demonstrate how Virtuoso fulfills this value proposition.</para>
		</sect2>
		<!-- ###################################################### -->
		<sect2 id="mpwrknldgwkr">
			<title>Empowering Knowledge Workers</title>
			<para>Your organization seeks to empower its knowledge workers
    by providing transparent access to corporate information so that they can make timely and
    accurate decisions. </para>
			<sect3 id="infrachal">
				<title>Infrastructure Challenges</title>
				<itemizedlist mark="bullet">
					<listitem>
						<para>Your organizations core business solutions are all driven by database engines
        provided by different database vendors</para>
					</listitem>
					<listitem>
						<para>The disparate application databases are hosted on a range of different database server
        machines running different operating systems</para>
					</listitem>
				</itemizedlist>
			</sect3>
			<sect3 id="critisucfctr">
				<title>Critical Success Factors</title>
				<itemizedlist mark="bullet">
					<listitem>
						<para>To maximize the uptake of this initiative, the knowledge workers must be abstracted
        from the intricacies of heterogeneous data access.</para>
					</listitem>
					<listitem>
						<para>Information must be available in real-time</para>
					</listitem>
					<listitem>
						<para>Information must be accurate</para>
					</listitem>
					<listitem>
						<para>Knowledge workers must be able to manipulate information and make decisions using their
        existing &quot;off the shelf&quot; desktop productivity tools.</para>
					</listitem>
				</itemizedlist>
			</sect3>
			<sect3 id="techchal">
				<title>Technology Challenges</title>
				<itemizedlist mark="bullet">
					<listitem>
						<para>The data residing in disparate data sources needs to be pulled together in real time
        to produce information</para>
					</listitem>
					<listitem>
						<para>High throughput transmission of information culled from disparate application databases
        to desktop productivity tools being used by the knowledge workers.</para>
					</listitem>
				</itemizedlist>
			</sect3>
			<sect3 id="techsoln">
				<title>Technology Solution</title>
				<para>Implement a 3-tier distributed computing architecture utilizing ODBC, JDBC, or
    OLE-DB for data access and OpenLink Virtuoso&#153; as your &quot;Data Junction Box&quot;.</para>
			</sect3>
			<sect3 id="solimpl">
				<title>Solution Implementation</title>
				<para>The infrastructure required in order to fulfill the objectives set would be assembled
    as follows: </para>
				<itemizedlist mark="bullet">
					<listitem>
						<para>Creation of &quot;Data Junction Box&quot; using a OpenLink Virtuoso&#153;, that holds
        references to tables hosted by your application database engines</para>
					</listitem>
					<listitem>
						<para>Hosting one or more of your OpenLink Virtuoso&#153; servers on one or more designated
        server machines. These machines could be dedicated application servers or one of the many
        database servers currently in use</para>
					</listitem>
					<listitem>
						<para>Creation of ODBC or UDBC data source names on the same machine as the OpenLink
        Virtuoso&#153; server. These data sources names will connect OpenLink Virtuoso&#153; to
        the different application databases within your computing infrastructure</para>
					</listitem>
					<listitem>
						<para>Creation of ODBC, JDBC, or OLE-DB data source names that reside on the desktop machines
        used by your knowledge workers. The data source names created will be used to connect
        ODBC, JDBC, and OLE-DB based desktop productivity tools to your OpenLink Virtuoso&#153;
        servers.</para>
					</listitem>
				</itemizedlist>
				<para>Once the infrastructure has been assembled in the manner described in the previous
    section, the stage is set for your knowledge workers to commence exploiting the benefits
    of transparent access to information culled from heterogeneous data sources. The entire
    process occurs via the use of their chosen &quot;off the shelf&quot; desktop productivity
    tools. </para>
				<para>The entire solution, its infrastructure, and constituent components are depicted below.</para>
				<figure id="imagewp14" float="1">
					<title>Virtuoso Empowering Knowledge Workers</title>
					<graphic fileref="wpImage31.gif" width="766px" depth="534px"/>
				</figure>
				<note>
					<title>Note:</title>
					<para>Databases depicted could be replaced with any ODBC compatible database engine.</para>
				</note>
			</sect3>
		</sect2>
		<!-- ###################################################### -->
		<sect2 id="imprvcustprosp">
			<title>Improving Customer &amp; Prospect Interaction via Your Corporate Web Site</title>
			<para>Your organization seeks to increase customer
    and prospect intimacy by implementing a database driven web site. The site offers
    customers and prospects online support, quotations, order processing, and product
    information.</para>
			<sect3 id="icpinfrachal">
				<title>Infrastructure Challenges</title>
				<itemizedlist mark="bullet">
					<listitem>
						<para>Your organizations core business solutions are all driven by database engines
        provided by different database vendors</para>
					</listitem>
					<listitem>
						<para>The disparate application databases are hosted on a range of different database server
        machines running different operating systems</para>
					</listitem>
					<listitem>
						<para>Security implications of corporate database exposure to the Internet</para>
					</listitem>
					<listitem>
						<para>Availability of &quot;Web to Database&quot; middleware for your Web Server.</para>
					</listitem>
				</itemizedlist>
			</sect3>
			<sect3 id="icpcritsucfctr">
				<title>Critical Success Factors</title>
				<itemizedlist mark="bullet">
					<listitem>
						<para>Data transmission throughput between internal databases and web pages</para>
					</listitem>
					<listitem>
						<para>Scalability of Web Servers, underlying &quot;Web to Database&quot; middleware, and
        participating database engines</para>
					</listitem>
					<listitem>
						<para>Information accuracy</para>
					</listitem>
					<listitem>
						<para>Data updates by site visitors must be routed to the appropriate internal database(s).</para>
					</listitem>
				</itemizedlist>
			</sect3>
			<sect3 id="icptechchal">
				<title>Technology Challenges</title>
				<itemizedlist mark="bullet">
					<listitem>
						<para>The data residing in disparate data sources needs to be pulled together in real time
        to produce information</para>
					</listitem>
					<listitem>
						<para>Delivery of high-performance information access to numerous concurrent site visitors</para>
					</listitem>
					<listitem>
						<para>Availability of operating system independent &quot;Web to Database&quot; middleware,
        providing you with the freedom to chose the most suitable operating system for the job at
        hand.</para>
					</listitem>
				</itemizedlist>
			</sect3>
			<sect3 id="icptechsoln">
				<title>Technology Solution</title>
				<para>Implement a 3-tier distributed computing architecture utilizing ODBC, JDBC, or
    OLE-DB for data access and OpenLink Virtuoso&#153; as your &quot;Data Junction Box&quot;.</para>
			</sect3>
			<sect3 id="icpsolimpl">
				<title>Solution Implementation</title>
				<para>The infrastructure required in order to fulfill the objectives set would be assembled
    as follows: </para>
				<itemizedlist mark="bullet">
					<listitem>
						<para>Creation of &quot;Data Junction Box&quot; using a OpenLink Virtuoso&#153;, that holds
        references to tables hosted by your application database engines</para>
					</listitem>
					<listitem>
						<para>Hosting one or more of your OpenLink Virtuoso&#153; servers on one or more designated
        server machines. These machines could be dedicated application servers, the same machine
        hosting your Web Server, or one of the many database servers residing behind your
        corporate firewall</para>
					</listitem>
					<listitem>
						<para>Creation of ODBC or UDBC data source names on the same machine as the OpenLink
        Virtuoso&#153; server. These data sources names should point to the different application
        databases within your computing infrastructure.</para>
					</listitem>
					<listitem>
						<para>&quot;Web to Database&quot; middleware and Application Server Development kit selection.
      </para>
					</listitem>
					<listitem>
						<para>Creation of ODBC, JDBC, or OLE-DB data source names on your Web Server for use by your
        &quot;Web to Database&quot; middleware for connectivity to OpenLink Virtuoso&#153; </para>
					</listitem>
					<listitem>
						<para>Use the OpenLink Virtuoso&#153; Stored Procedure language to implement the data access
        and manipulation aspects of your application logic.</para>
					</listitem>
				</itemizedlist>
				<para>Once the infrastructure has been assembled in the manner described above, the stage is
    set for you to develop and implement your database driven web. The application development
    process retains a single as opposed to multiple database focus due to the sophisticated
    VDB Engine functionality provided by OpenLink Virtuoso&#153; without compromises in
    performance, security, or scalability. </para>
				<para>The entire solution, its infrastructure, and constituent components are depicted in the
    illustration that follows.</para>
				<figure id="imagewp15" float="1">
					<title>Internet Application Server Solution</title>
					<graphic fileref="wpImage32.gif" width="780px" depth="536px"/>
				</figure>
			</sect3>
		</sect2>
	</sect1>
	<!-- ###################################################### -->
	<sect1 id="featfunc">
		<title>Feature &amp; Functionality Comparisons</title>
		<para>There are a number of competing products that exist
    today, even though these products may not identify themselves as Virtual Database
    products. </para>
		<table colsep="1" frame="all" rowsep="0" shortentry="0" tocentry="1" tabstyle="decimalstyle" orient="land" pgwide="0">
			<title>Features Comparison</title>
			<tgroup align="char" charoff="50" char="." cols="12">
				<colspec align="left" colnum="1" colsep="0" colwidth="20pc"/>
				<thead>
					<row>
						<entry/>
						<entry>VDB Type</entry>
						<entry>Heterogeneous Joins</entry>
						<entry>ODBC Based Ext. data I/O</entry>
						<entry>Native data I/O</entry>
						<entry>ODBC Driver available</entry>
						<entry>JDBC Driver available</entry>
						<entry>OLE-DB Provider available</entry>
						<entry>Web Browser based Admin</entry>
						<entry>Cross Platform Support</entry>
						<entry>Full Database Functionality</entry>
						<entry>Multi- Threaded</entry>
					</row>
				</thead>
				<tbody>
					<row>
						<entry>OpenLink Virtuoso&#153;</entry>
						<entry>10</entry>
						<entry>Y</entry>
						<entry>Y</entry>
						<entry>Y</entry>
						<entry>Y</entry>
						<entry>Y</entry>
						<entry>Y</entry>
						<entry>Y</entry>
						<entry>y</entry>
						<entry>Y</entry>
						<entry>Y</entry>
					</row>
					<row>
						<entry>Microsoft SQL Server 7</entry>
						<entry>8</entry>
						<entry>Y</entry>
						<entry>Y</entry>
						<entry>N</entry>
						<entry>Y</entry>
						<entry>N</entry>
						<entry>Y</entry>
						<entry>N</entry>
						<entry>N</entry>
						<entry>Y</entry>
						<entry>Y</entry>
					</row>
					<row>
						<entry>IBM DataJoiner</entry>
						<entry>10</entry>
						<entry>Y</entry>
						<entry>Y</entry>
						<entry>Y</entry>
						<entry>Y</entry>
						<entry>Y</entry>
						<entry>N</entry>
						<entry>N</entry>
						<entry>P</entry>
						<entry>P</entry>
						<entry>N</entry>
					</row>
					<row>
						<entry>Inprise BDE</entry>
						<entry>3</entry>
						<entry>N</entry>
						<entry>Y</entry>
						<entry>N</entry>
						<entry>N</entry>
						<entry>N</entry>
						<entry>N</entry>
						<entry>N</entry>
						<entry>N</entry>
						<entry>N</entry>
						<entry>N</entry>
					</row>
					<row>
						<entry>Microsoft JET</entry>
						<entry>4</entry>
						<entry>Y</entry>
						<entry>Y</entry>
						<entry>N</entry>
						<entry>N</entry>
						<entry>N</entry>
						<entry>Y</entry>
						<entry>N</entry>
						<entry>N</entry>
						<entry>P</entry>
						<entry>N</entry>
					</row>
					<row>
						<entry>Symantec DBAnywhere</entry>
						<entry>5</entry>
						<entry>N</entry>
						<entry>Y</entry>
						<entry>N</entry>
						<entry>N</entry>
						<entry>Y</entry>
						<entry>N</entry>
						<entry>N</entry>
						<entry>N</entry>
						<entry>N</entry>
						<entry>N</entry>
					</row>
				</tbody>
			</tgroup>
		</table>
	</sect1>
	<!-- #################################################### -->
	<sect1 id="cnclsn">
		<title>Conclusion</title>
		<para>Virtual Database technology is clearly
    critical technology with inherent impact on Universal Data Access, Distributed Computing
    and the emerging Information Age. </para>
		<para>The Internet as the distributed computing medium of choice will continue to create
    insatiable demand for information. This simply increases the pressure on information
    producers and consumers to retrieve data and then rapidly convert into information at ever
    increasing rates.</para>
		<para>Internet/Intranet/Extranet sites will emerge as the dominant medium through which
    information is exchanged. Information once obtained would then be rapidly converted in to
    knowledge the ultimate basis of competitive advantage and power.</para>
		<para>If the Information Age is the next point of call, and we accept that all Information
    comes from data? Then it is rational to conclude that Virtual Databases will lie at the
    heart of the Information Age. In short, there is a limited Information Age at best without
    the prevalence of Internet/Intranet/Extranet sites driven by Virtual Database Engines.</para>
	</sect1>
</chapter>