Chapter 4: Relational Model

Question 1

What are primary keys (PK) and foreign keys (FK)?

Answer 1

A primary key uniquely identifies a record in a table. A foreign key is an attribute in one table that links to the primary key in another table

Question 2

What is the structure of a relation in the relational model?

Answer 2

A relation consists of a set of tuples (rows), each of which contains attributes (columns). The degree refers to the number of attributes, and the cardinality refers to the number of tuples in the relation.

Question 3

What are the different types of data integrity constraints?

Answer 3

Types of data integrity constraints include entity integrity (ensuring that no primary key value is null), referential integrity (ensuring foreign keys match primary keys), and semantic integrity (enforcing business rules).

Question 4

What is Data Manipulation Language (DML)?

Answer 4

DML is used to query, insert, update, and delete data in a relational database.