LIS 558 - Database design problems
As an example of a design that creates problems,
suppose that we have a bibliographic database of scientific
and that, for each article,
we include the names
and institutional affiliations of the authors.
Redundancy is unnecessary repetition of data.
If we include the institutional affiliation
with every article written by a given author,
this seems redundant.
We should be able to store the institional affiliation
in one place.
When authors change their institutional affiliations,
should all the relevant bibliographic records be updated?
how can we be sure of catching all the relevant records?
The form of an author's name can vary slightly
from one article to another.
Suppose we want to enter information
on the institutional affiliation
of a scientist who has not written
any of the articles in our database.
Do we create a dummy article?
Do we try to find an article written by this person to include,
even if the topic of the article
does not fall within the scope of the database?
If, when weeding our database,
we happen to delete all articles by a particular scientist,
will we lose the information
on the scientist's institutional affiliation?
Scientific articles often have more than one author.
What do we do with additional authors?
If we add a bibliographic record for each author,
repeating the same other information (title, source, etc.)
about the article,
this is redundant,
as well as creating other problems.
If we add fields for second author, third author, and so on,
how many fields do we add?
Field space will be wasted for articles with only one or two
Searching by author name
or creating a list of authors
also becomes more complicated.
If we include all the authors' names in a single field,
how will we search for a single authorís name
or create a list of authors?
How will we match the right institution to the right author?
Various design techniques,
including entity-relationship modeling
can be used to overcome certain problems
arising from poor database design.
Last updated July 5, 2001.
This page maintained by
Prof. Tim Craven
E-mail (text/plain only): firstname.lastname@example.org
Faculty of Information and
University of Western
Canada, N6A 5B7