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the user. The drawback of dynamic connections is that there is a (much) bigger server load due
to preprocessing.
4.2 General Architecture
For a basic WWW database interface the following steps are necessary:
1. Generate the user interface (HTML form)
2. Receive user input via HTTP (e.g. WWW server with an Common Gateway Interface (CGI)
or application programming interface (API))
3. Analyze user input, derive query, and pass it to the DB client
4. Access the database (e.g. network client for a database or a server demon process)
5. Generate HTML from the output and send it back to the user
Figure 3 shows different ways to
achieve this. The easiest way is
using a static HTML form, processing
it with a CGI script, and
using a network client of the
database. Using the application
program interface (API) of the
webserver instead of the CGI
speeds up the processing, but is
less portable.
A little bit more sophisticated
and faster is a database demon
DB
process that keeps the database
DB-server
open and waits for queries instead
of the network client. De- Figure 3: Different ways of database integration
pending on the speed of the network
connection and the size of the database, this may speed up queries by a factor of five or
so. Another improvement is a HTTP interface to the demon process thus offering a database
that can be directly accessed from the browser. Our own experiments have shown this may
again speed up queries by a factor of five or so, depending on the speed of the network connection
to the Database-/Webserver.
4.2.1 Forms interface
The forms interface allows the user to formulate a query or other database operations using the
following HTML 2.0 elements [23]:
• Input Field: INPUT
• Text Field: INPUT TYPE=TEXT
Allows for text input.
HTTP:x
WWW-Browser
HTTP:y
• Password Field: INPUT TYPE=PASSWORD
As above, except that the value is obscured as it is entered.
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HTTP-Demon
CGI
DB-Client
Proprietary:z
DB-Demon
ESQL
WWW-server
API