Topic 3: Database Concepts I

Question 1

Attributes

Answer 1

Characteristics of entities.

Question 2

Cardinality

Answer 2

The specific number of allowed entity occurrences associated with a single occurrence of the related entity by assigning a specific value to connectivity.

Question 3

Client–server System

Answer 3

A computing model that is based on distributing functions between two types of independent and autonomous processes: clients and servers.

Question 4

Composite Key

Answer 4

A combination of more than one attribute to form one primary key. It indicates an M:N (many-to-many) relationship between the columns.

Question 5

Conceptual Models

Answer 5

Models that focus on a logical view of what is represented in the database.

Question 6

Controlled Redundancies

Answer 6

Redundancies that are allowed for the convenience of structuring data, data manipulation or reporting.

Question 7

Data

Answer 7

Raw facts relating to or describing a single business transaction or event.

Question 8

Data Anomalies

Answer 8

Inconsistencies or errors that exist in a database because of entry or changes.

Question 9

Data Integrity

Answer 9

Consistent and correct representation regardless of where data are sourced from within a file system.

Question 10

Data Redundancy

Answer 10

The situation where the same data are recorded and stored in multiple locations, which can lead to data inconsistency and anomalies.

Question 11

Database

Answer 11

A shared computerised structure that captures, stores and relates data.

Question 12

Database Administrator

Answer 12

A person who controls access by users to the database, maintains the data dictionary and oversees backup and recovery in the DBMS.

Question 13

Database Management System (DBMS)

Answer 13

A group of programs that manipulate the database and provide the interface between the database and the user as well as other application programs.

Question 14

Database Models

Answer 14

Diagrams of data entities and their relationships.

Question 15

Database System

Answer 15

A system of hardware, software, people, procedures and data that allow the capture, storage, management and use of data within a database environment.

Question 16

Deletion Anomalies

Answer 16

Data anomalies that occur when the deletion of data about an entity inadvertently deletes data about another entity.

Question 17

Entities

Answer 17

Representations of real-world things or objects that are involved in a process and correspond to a table in a relational database.

Question 18

Entity–relationship Model

Answer 18

A data model that graphically depicts relationships between entities and attributes.

Question 19

External Models

Answer 19

Models that relate to the end-users’ views of data.

Question 20

Field

Answer 20

A characteristic of a record that contains data that have a specific meaning.

Question 21

File

Answer 21

A collection of records that are related.

Question 22

Foreign Key

Answer 22

An attribute whose values must match the primary key in another table.

Question 23

Hardware

Answer 23

Physical devices including the computer and network.

Question 24

Implementation Models

Answer 24

Models that show how the data are represented in the database, including the structures implemented.

Question 25

Information

Answer 25

Data or facts that are processed in a meaningful form.

Question 26

Insertion Anomalies

Answer 26

Data anomalies that occur when new data are entered into the file and not all occurrences are updated.

Question 27

Logical Representation

Answer 27

A model that represents data and their relationships independent of hardware and software. This representation can then be used to select a database management system (DBMS).

Question 28

Many-to-many Relationship (M:N)

Answer 28

A relationship between two entities in which the cardinality of both entities in the relationship is many.

Question 29

Modification Anomalies

Answer 29

Data anomalies that occur when a field value is changed and not all occurrences are updated.

Question 30

Normalisation

Answer 30

A set of rules and a process of assigning attributes to entities to eliminate repeating groups and data redundancies, and to form tables representing entities that promote structural and data independence.

Question 31

One-to-many Relationship (1:N)

Answer 31

A relationship between two entities in which the cardinality of one entity in the relationship is one and the other entity’s cardinality is many.

Question 32

One-to-one Relationship (1:1)

Answer 32

A relationship between two entities in which the cardinality for each entity is one.

Question 33

Operating System

Answer 33

Computer programs that control hardware to interface with software application programs.

Question 34

Physical Representation

Answer 34

A model that presents all the database storage details including all specifications for hardware and software.

Question 35

Primary Key

Answer 35

An attribute (or column) that uniquely identifies a particular object (or row).

Question 36

Procedures

Answer 36

The instructions and rules that govern the design and use of the software outside programming.

Question 37

Record

Answer 37

A connected set of fields that describes a person, place or thing.

Question 38

Relational Database

Answer 38

A database that stores data in a number of tables.

Question 39

Software

Answer 39

Computer programs that are written in programming languages or code that instruct the operations of a computer.

Question 40

Structural Independence

Answer 40

A data attribute that exists when changes in the database structure do not affect access.

Question 41

Structured Query Language (SQL)

Answer 41

A database query language that allows the user to specify what must be done without having to specify how it is to be done.

Question 42

Table

Answer 42

A collection of columns (attributes) and rows (objects) that describe an entity.