A.2 The Relational Database Model

Question 1

Database Management System

Answer 1

System software for creating and managing databases.
Provides users and programmers with a systematic way to create, retrieve, update and manage data

Question 2

Relational database management system (RDBMS)

Answer 2

–> A database management system based on the relational model

–> Stored in database objects which are called tables

–> Each table are broken up into smaller entities called fields.

Question 3

Record

Answer 3

A row of data is rach individual entry that exists in a table

Question 4

Column

Answer 4

A vertical entity in a table that contains all information associated with a specific field in a table

Question 5

Functions and tools of a DBMS

Answer 5

1. Organises Data –> organized or structured according to the specifications
2. Integrates Data –> Data is linked together so that it can be assembled into combinations during the execution of particular applications.
3. Separates Data –> serves as a filter between application programs and their associated data.
4. Controls Data –> controls where data is physically stored.
5. Retrieves Data –> record of data can be obtained via DBMS
6. Protects Data –> protects the data and relational elements from unauthorized users, physical damage, operating system failure, etc.

Question 6

Security of DBMS

Answer 6

Data validation, access rights and data locking are all features that promote data security.

Question 7

Schema

Answer 7

The logical structure of data in the database

Question 8

Conceptual Schema

Answer 8

A basic model that contains entities and the relationship between them

Question 9

Logical Schema

Answer 9

Each entity in the conceptual schema is converted into either a table, field, or object with any restrictions needed.

Question 10

Physical Schema

Answer 10

It contains the name of the tables, a list of fields in each table, and relationships between tables that are specific to database management software.

Question 11

Nature of Database Dictionary

Answer 11

Contains data about each file in the database and each field within those files

Question 12

Data Definition Language (DDL)

Answer 12

Programming language used to define and create database schemas.

Question 13

Table

Answer 13

The place where records and fields are stored

Question 14

Record

Answer 14

Groups of related fields

Question 15

Field

Answer 15

Combination of one or more one character

Question 16

Primary Key/ Candidate Key

Answer 16

Unique key field which identifies a record in the table

Question 17

Secondary key

Answer 17

A unique key field which identifies a record in another table

Question 18

Composite Secondary key

Answer 18

Combination of more than 1 primary key

Question 19

Join

Answer 19

Collection of fields

Question 20

One to One

Answer 20

When each record in one table is linked to only one record in the other table.

Question 21

One to Many

Answer 21

One row in table A may be linked with many rows in table B, but one row in table B is linked to only one row in table A

Question 22

Many to Many

Answer 22

When one or more items in one table can have a relationship to one or more items in another table

Question 23

Issues Caused by Redundant Data

Answer 23

Insertion Anomalies –> new rows –> duplicate data

Deletion Anomalies –> Deleting rows may cause a loss of data

Update Anomalies –> inconsistency in the data that happens after database is updated

Question 24

Referential Integrity

Answer 24

Refers to the relationship between tables.

–>It maintains the primary keys that are used to create a normalized database.

Question 25

1NF

Answer 25

One table

Question 26

2NF

Answer 26

Multiple tables that rely on primary keys

Question 27

3NF

Answer 27

Eliminates non-primary keys from relying on other non-primary keys

Question 28

Different data types (9)

Answer 28

Text
Numeric
AutoNumber
Currency
Date
Memo
Yes/No
Hyperlink
Object (photos, videos, audios)

Question 29

Construct a relational database to 3NF using objects such as tables, queries, forms, reports, and macros

Answer 29

-

Question 30

Construct an Entity-Relationship diagram (ERD) for a given situation

Answer 30

-

Question 31

Simple Query

Answer 31

Simple queries are made using one table.

Question 32

Complex Query

Answer 32

Complex queries are made using multiple tables and complex conditions

Question 33

SQL Statement

Answer 33

SELECT LastName, Phone,Email
FROM STUDENT
WHERE EMAIL LIKE “%@gmail.com”