TOPIC 2 RELATIONAL DATABASE

Identify a commonly used Relational Database Management System (RDBMS) in industry applications.

• MongoDB

• MySQL

• Redis

• Neo4jRRD

Identify the relational database component that represents the number of tuples in a relation.

• Degree

• Attribute

• Cardinality

• Domain

Determine the correct description of a relation schema in a relational database.

• Current data stored in a table

• Physical storage of records in memory

• Result of relational algebra expression

• Logical structure consisting of relation name, attributes, and domains

Differentiate the role of a relation instance in relational database design.

• Represents the actual data at a specific time

• Ensures referential integrity

• Identifies candidate keys

• Defines attribute constraints

Interpret the purpose of Entity Integrity Rule in a relational database.

• Ensures foreign key values exist in referenced table

• Prevents duplicate candidate keys

• Prohibits NULL values in primary key attributes

• Restricts domain values

Select a fundamental relational algebra operator that filters rows based on a condition.

• Projection (π)

• Union (∪)

• Selection (σ)

• Join

Explain the main purpose of the Projection (π) operator in relational algebra.

• Filter tuples based on condition

• Select specific attributes from a relation

• Remove duplicate tuples

• Combine two relations

Apply relational algebra concepts to determine the output of
π StudentName (STUDENT)

• All rows from STUDENT table

• STUDENT table with filtered rows

• Only StudentName column from STUDENT

• Combination of STUDENT and another table

Assess the condition required for Union (∪) operation between two relations.

• Different number of tuples

• Same primary key

• Union compatibility between relations

• Identical data values

Analyze the following relational algebra expression:

σ Department = 'IT' (EMPLOYEE)

Determine the result produced by the expression.

• Only Department attribute from EMPLOYEE

• All attributes of EMPLOYEE with only tuples from IT department

• All tuples from EMPLOYEE without condition

• Combination of EMPLOYEE and DEPARTMENT tables