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Entities and
Attributes
Entities are specific objects or
things in the mini-world that are represented in the
database.
For example the EMPLOYEE John
Smith, the Research DEPARTMENT, the ProductX PROJECT.
Attributes are properties used to
describe an entity.
For example an EMPLOYEE entity
may have the attributes Name, SSN, Address, Sex, BirthDate .
A specific entity will have a
value for each of its attributes.
For example a specific employee
entity may have Name='John Smith', SSN='123456789', Address ='731, Fondren,
Houston, TX', Sex='M', BirthDate='09-JAN-55‘
Each attribute has a value set
(or data type) associated with it – e.g. integer, string,
subrange, enumerated type,
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