Chapt.5 - Relational Database Model

___is used to describe a relation. It is made up of a relation, R, and a list of attributes A₁, A₂, ..., A_n.

• relation schema
• relational state

• database structure
• attribute domain

A relation of degree seven, which stores information about university students, would contain ___ attributes describing each student.

• 7
• 3
• 1
• 5

Identify the parts labeled A, B and C

• A: Relation name, B: Tuples, C: Attributes

• A: Attributes, B: Tuples, C: Relation name

• A: Attributes, B: Relation name, C: Tuples

• A: Relation name, B: Attributes, C: Tuples

___is used to uniquely identify individual tuples in a relation.

• Foreign Key
• Index
• Unique Key
• Primary Key

___represent attributes whose values are unknown or do not exist for some individual tuple.

• None
• NaN
• Undefined
• NULL

What does it mean to say that a database displays both entity integrity and referential integrity?

• each row has a unique identifier, and each column has a unique identifier.

• each table has a unique identifier, and each row has a unique identifier.

• each row has a unique identifier, and relationships between tables are maintained.

• each column has a unique identifier, and relationships between tables are maintained.

___constraint states that a tuple in one relation that refers to another relation must refer to an existing tuple in that relation.

• foreign key
• referential integrity
• entity integrity
• data integrity

___operation is a filter that keeps only those tuples that satisfy a qualifying condition.

• Project

• Join
• Select

• Union

If we are interested in only certain attributes of a relation, we use the ___ operation.

• division
• selection
• projection
• join

The result of this operation is a relation that includes all tuples that are in both R and S.

• Difference
• Intersection
• Union
• Join