Database - Data Modeling with ER Model - Discussion
Discussion Forum : Data Modeling with ER Model - General Questions (Q.No. 11)
11.
An attribute that names or identifies entity instances is a(n):
Discussion:
2 comments Page 1 of 1.
Lovepreet said:
1 decade ago
Please describe in detail.
Sairam said:
7 months ago
An identifier is an attribute (or a combination of attributes) that uniquely names or identifies individual instances of an entity.
Example:
The attribute Student_ID can serve as an identifier for an entity called Student because it uniquely identifies each student in the database.
For an entity Employee, the attribute Employee_ID can act as an identifier.
Why Not the Other Options?
Entity: Refers to the object being represented, not the specific attribute that identifies it.
Attribute: Refers to any property of an entity, but not necessarily one that uniquely identifies it.
Relationship: Refers to the association between entities, not an attribute.
So, the identifier is the specific attribute used to uniquely identify an entity instance.
Example:
The attribute Student_ID can serve as an identifier for an entity called Student because it uniquely identifies each student in the database.
For an entity Employee, the attribute Employee_ID can act as an identifier.
Why Not the Other Options?
Entity: Refers to the object being represented, not the specific attribute that identifies it.
Attribute: Refers to any property of an entity, but not necessarily one that uniquely identifies it.
Relationship: Refers to the association between entities, not an attribute.
So, the identifier is the specific attribute used to uniquely identify an entity instance.
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