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Re: Full Name as Composite Attribute

From: vldm10 <vldm10_at_yahoo.com>
Date: 28 Mar 2005 20:44:46 -0800
Message-ID: <1112071486.928942.60850@o13g2000cwo.googlegroups.com>


I would like to add a few thoughts about the composite attribute "Address" from previous thread. "Address" can be defined as a relation among the entities: State, City, StreetName, Building and Apartment. There are State or City services which initialize a new street or building or house in the system or delete some of these entities from the system and there are technical procedures for these actions. These databases are used by the Post Office, Water, Electric, Gas, Phone companies, some courts etc. These are big systems that need to know about all the buildings in one street, (i.e. a relationship). These systems require a list of streets, a list of buildings, a list of cities and their relationships. Here, the address should be treated as a relationship.
We can also treat Address as an entity and form a relationship between the entity Person and the entity Address. On the other hand, we can form an entity Person with a PersonName as an attribute and an address as a composite attribute. Here, we have an entity with attributes.
We can see that the solution as relationship is more powerful; it is not just a set of data. Just to mention two reasons why this is so: The Relation solution can support the fact that one person has 2 or more addresses. It also can support the case in which one person had one address in two different time periods. The other advantage of this solution is that it presents a clearer picture about reality, regarding our knowledge of it.
On the other hand, there is an advantage of this entity approach for simpler systems; we don't need to build some complex and expensive solutions.

Regarding the "Full Name" composite attribute, the situation can be more complex, because giving names can be a very complex procedure. Here is one example; we are supposed to create a DB with Donald Duck, Mickey Mouse and some other Walt Disney characters. We can put them into tables, create tables with them, create some of their relationships, i.e. - we can create a Relational DB. But, although people know much about these characters, even their personalities, they are not from the real world; Walt Disney made them up. So, there is no Conceptual Model because there is no mapping from the real world for these full names.
In fact Frege's theory about names can explain similar examples. I think that those members of this group who are good at Semantics and Mathematical Logic can give us more valuable comments about theory of names.

Vladimir Odrljin Received on Mon Mar 28 2005 - 22:44:46 CST

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