A
telephone book is an example of a manual database. The telephone book is an
efficient database when searching for a telephone number, given a name. The
telephone book is not efficient when searching for the names of people living
in a certain street or when searching for the name of a person with a certain
phone number. Yet the telephone book contains all of this information.
The efficiency of a database can generally be determined by the ability of the database to answer all required questions and by the time it takes to answer the questions. Relational databases are made up of data stored in tables from which almost all (90%) required questions of the database may be answered.
Suppose the information in a telephone book were to be placed in a more efficient database and made readily available to the public. What extra information becomes available? How can this be helpful? Could this be a threat to privacy?