Chapter 3, Problem 19RQ

Explanation of Solution

Homonyms:

When more than one attributes have the same name, they are referred as “homonyms”.

It indicates the use of same name to label different attributes.

Example:

Suppose in table “STUDENT”, one of the attribute names is “student_number”. Also, in table “PROFESSOR”, there exists an attribute with name “student_number”. Then both the attributes are named as “Homonyms”.

Synonyms:

When more than one name is assigned to same attribute, the attribute names are referred as “synonyms’. It exists when the same attribute has more than one name.

Example:

Suppose in table STUDENT, one of the attribute names is “STU_NUM” which displays the student registration number. Also, another attribute is “STU_ID” which also displays the student registration number. Then the attribute names are named as “Synonyms”.

Homonyms and Synonyms in Database design:

The use of homonyms and synonyms should be avoided in database design. This is due to the following reason:

• To avoid inconsistency in the database design.

  For example:

  Suppose we check the database for a specific attribute such as “ID”. If “ID” refers to student ID as well as to professor’s ID, a clear case of a homonym, it is a creation of an ambiguity, because it is no longer clear which entity the “ID” belongs to...