An Introduction to JDBC
types of information about a table.
Example:
At Mitre, we collect information from the internet using commercial
search engines such as Altavista and Lycos for a variety of topics.
This information is stored as a collection of text documents for any
topic. The collection can be searched via keywords. We use a public
domain search engine Glimpse from the University of Arizona to index
and search the document collection.
Some of the document collections can be fairly large (over 1500
documents). If a common keyword is used, then the list of matching
documents will be large. We decided to display the results from the
search engine using Java and JDBC to avoid scanning long lists of
matching documents. Java was used to build a 3D space and plot circles
at locations in the 3D space to represent the frequency of the
occurrences of keywords in a document. JDBC was used to retrieve the
titles of the documents which were stored in a table. Passing all the
titles of all documents in the collection as parameters to the Java
applet would increase the time to load the applet significantly.
Glimpse returns the frequency of occurrence of a keyword in a
document. We use that number to locate a circle representing the
document in 3D space (Fig.3). Each axis represents a keyword. If fewer
than 3 keywords are used, then documents will be displayed in a plane
or on a line. If more than 3 keywords are used, then 3 or fewer
keywords must be chosen to display matching documents. The frequency
of occurrence of keywords was normalized for each axis. The
frequencies of keywords in documents was passed as parameters to the
applet. The color was the circle was computed based on the position of
the circle in the 3 axes. Red was used for documents on the z-axis,
green was used for documents on the y-axis, and blue was used for
documents in the x-axis. Brighter shades of the 3 primary colors were
used for documents with higher keyword frequencies. A mix of the
primary colors was used for circles which contained more than one
keyword.
Fig.3
JDBC was used to retrieve the titles for documents which contained
non-zero occurrences of the keywords. This number was usually fewer
than the total number of documents when a fairly unique keyword was
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