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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title> SECONDO </title>
<meta name="description" content="extensible database system" />
<link rel="stylesheet" type="text/css" href="secondo.css">
<link rel="shortcut icon" href="favicon.ico">
</head>
<body onload="window.status='SECONDO - An extensible database system'">
<div align="center">
<table summary="">
<tr><td> <img alt="FernUni Hagen" src="images/feulogo.gif" width="363" height="78"></td></tr>
<tr><td> <img alt="SECONDO" width="598" height="107" src="images/logo.gif"> </td></tr>
<tr><td><h1> An Extensible Database System </h1></td></tr>
</table>
</div>
<h2> What is <span class="secondo">Secondo</span> </h2>
<div class="short">
<span class="secondo">Secondo</span> is an extensible database system supporting
especially non-standard applications. Designed at the FernUniversität in Hagen,
<span class="secondo">Secondo</span> is a platform for implementing and experimenting
with various kinds of data models.
</div>
<h2> Target Groups </h2>
<div class="short">
<span class="secondo">Secondo</span> can be used by groups at universities to pursue
and prototype their research ideas for database systems. It can be used in teaching
to show students in detail the architecture and implementation of database systems.
Additionally, <span class="secondo">Secondo</span> may be interesting for users in need
of a database system able to handle non-standard data types usually not supported
by standard systems.
</div>
<h2> Benefits </h2>
<div class="short">
The <span class="secondo">Secondo</span> system is extensible by algebra modules, using
a well defined interface. New data models and data structures together with their operations
are integrated into the system in this way. The source code is available and enables the
user to access and modify every part of the database system. <span class="secondo">Secondo</span>
comes with a carefully written user manual, programmer's guide and installation instructions.
</div>
<h2> Functionality </h2>
<div style="text-indent:2cm;">
<img src="images/architecture.gif" alt="Architecture" width="317" height="276"><br>
</div><br>
<div class="short">
Objects of an arbitrary type defined in one of the
<span class="secondo">Secondo</span> algebra modules can be stored in a database.
The following list shows some of the available
algebras:
<ul class="algebra">
<li> <span class="algebraname"> Standard-Algebra </span> <br>
provides simple types like integer, real, bool and
string and operations on those types.<br><br>
</li>
<li> <span class="algebraname"> Relational-Algebra </span> <br>
contains data types and operations to realize a
classical relational database system.<br><br>
</li>
<li> <span class="algebraname"> Spatial-Algebra </span> <br>
represents geometrical objects such as points,
lines and regions together with spatial operations.<br><br>
</li>
<li> <span class="algebraname"> Temporal-Algebra </span> <br>
represents moving objects in databases, e.g.
peoples or vehicles and allows one to formulate
queries about their movements.<br>
</li>
</ul>
</div>
<h2> Query Example </h2>
<div class="short">
Using these algebras, one can determine the names
and addresses of all Italian restaurants in Berlin, which
have a distance smaller than 2 km to the Brandenburg
Gate. Then, the result is presented graphically.
</div>
<pre>
select [r:name, r:strasse, r:geoData]
from [restaurants as r, sehenswuerdpoi as s]
where [ s:name="Brandenburger Tor",
r:art="Italienisch",
distance(r:geoData, s:geodata) < 2000]
</pre>
<br><br>
<div style="text-indent:2cm">
<img src="images/screenshot1.gif" width="640" height="495" alt="Screenshot">
</div>
<br><br>
<div class="footnote">
Last Changed: 2009-08-06
</div>
</body>
</html>