Papers in PDF format

available all over the world. If you like, you can restrict the access to the users you like to be
able to access your data. Usually you will need only a single user database license. The graphical
user interface is easy to use and well known, people do not have to deal with different
platforms and keyboard codes. Last not least the WWW is developing very fast, new tools are
announced nearly every day. These tools can be used e.g. for your database perhaps allowing
to provide „database access“ to your data without even having a database.
Unfortunately there are also some limitations of the WWW:
• There are only few interface elements and control of the representation is limited.
• Every action you take usually will require an interaction with the server.
• A stateless protocol may have some problems for your application. However at the first
WWW conference it was reported [22] that even this may be an advantage as it forces a
different, very modular design.
4.1 File System versus Database
In the WWW traditionally the file system („server tree“) has been used to provide documents.
There are, however, good reasons to use a database instead of a file system for special applications
or even for the whole server tree.
A database allows comfortable maintenance of the data, for example:
• Administrative data can be easily included into documents
• Unified appearance of all documents on the server can be ensured
• All documents of a specific author can be retrieved
• User profiles can be used to offer multiple languages
• Filters can translate document types in the requested form
• A database has been constructed to store data in a reliable way, that is, each database has to
comply to the Atomicity, Consistency, Isolation, Durability (ACID) principle of transactions.
These features are important if data in the atabase d should be changed.
As advantage of the file system there are two points I want to mention:
• It is really easy to use, as everybody has to use it every day
• There is only one system to care for. There are no problems with another, perhaps remote
system, the database (-server). I think you all know these troubles with different operating
systems, versions, patches, etc. :-)
Using a file system you can offer static and dynamic connections. A static connection is one
which uses only the server tree. This allows fast access, can be used by robots and the tree
structure can be easily understood by the user in the most cases.
We use the term dynamic connection if a Common Gateway Interface (CGI) script is involved.
These kind of scripts will usually have names like getpage.pl and will be called with parameters
including user specific. Such an URL could look like this:
In this case the document doia.htm will be fetched in the language „de“ (German) considering
the user profile of „bittorf“. This user profile may contain information about the allowed IP
addresses, the display resolution of the associated computers, gamma correction parameters,
etc. The document may then be processed according to this user profile before being offered to
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