The values of the attributes in a database describe a particular __________.
2021
The values of the attributes in a database describe a particular __________.
- A.
Entity
- B.
Tuple
- C.
Field
- D.
View
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Correct answer: A
Explanation:
In the relational and ER data models, an entity is the real-world object or concept that a database models (e.g., a Student, a Course, an Order). Its attributes are the properties that characterize it, and it is precisely the values of those attributes that describe one particular instance of that entity — that is the identity this question is testing.
Entity: An entity represents a real-world object, concept, or event about which data is stored (e.g., a Student, a Course, an Order). Attributes are properties of an entity. The values of the attributes for a specific instance of an entity are exactly what describes that particular entity instance.
Tuple: A tuple is a single row in a database table. It represents a specific instance of an entity type and contains the values for all attributes of that instance. While a tuple contains the values, the values themselves describe the entity instance represented by the tuple. The question asks what the values describe.
Field: A field (or column) represents a single attribute across all rows. It defines the type of characteristic being stored (e.g., the 'Name' field stores names). It doesn't describe a particular entity instance; it describes one characteristic shared by all instances in that column.
View: A view is a virtual table based on the result-set of an SQL query. It does not represent a single real-world object described by attribute values in the same way a base table row does.
Based on these definitions, the values of the attributes for a specific record collectively describe a particular instance of an Entity.