Database Systems

Question 1

Flat file database

Answer 1

Flat file database consists of a single table and contains files, records, fields and characters. Simple to create, easy to use, and inexpensive. Increased data redundancy and inconsistency

Question 2

Relational database

Answer 2

Relational database is comprised of multiple entities, contains attributes and relationships. Reduced data redundancy, consistency, shared data centralised security. Takes time to set up.

Question 3

Primary key

Answer 3

A primary key is a field that is unique to any given record. It is referred to as
a unique identifier that uniquely identifies records.

Question 4

Foreign key

Answer 4

A foreign key is any field in table which is the primary key in another table

Question 5

Databases

Answer 5

Databases are a persistent and organised store of data.

Question 6

Database benefits

Answer 6

Makes processing more efficient. Reduces storage requirements by avoiding redundancy. Allows different users to only see relevant data.

Question 7

Database Management System

Answer 7

A manipulation language to change and access data. Integrity to ensure efficiency and structure is not compromised. Additional security. An interface for other programs to access the data. Program/data independence – You can change the data without affecting the program and vice versa.

Question 8

Entity Relationship Modelling

Answer 8

Entity relationship modelling entails taking a real world situation and representing it using an entity relationship diagram. There are 3 types of relationships: 1 to 1, 1 to many or many to 1 and many to many.

Question 9

Data dictionary

Answer 9

A ‘data dictionary’ describes the structure and attributes of data ‘items’ to be
used within a database. A data dictionary includes the names and descriptions of the tables and the fields contained in each table.