Chapter 8 - Databases

Question 1

Data base

Answer 1

Structured collection of items of data that can be accessed by different applications programs

Question 2

Relational database

Answer 2

A database where the data items are linked by internal pointers

Question 3

Table

Answer 3

Group of similar data, in a database, with rows for each instance of an entity and columns for each attribute

Question 4

Record

Answer 4

A row in a table in a database

Question 5

Field

Answer 5

Column in a database

Question 6

Tuple

Answer 6

One instance of an entity, which is represented by a row in a table

Question 7

Entity

Answer 7

Anything that can have data stored about it, eg. A person, place, event, thing

Question 8

Attribute

Answer 8

An individual data item stored for an entity eg. Person attributes could be name, address etc

Question 9

Candidate key

Answer 9

An attribute or smallest set of attributes in a table where no tuple has the same value

Question 10

Primary key

Answer 10

Unique identifier for a table. Special case for a candidate key

Question 11

Secondary key

Answer 11

Key that is an alternative to the primary key

Question 12

Foreign key

Answer 12

Set of attributes in one table that refer to the primary key in another table

Question 13

Relationship

Answer 13

Situation in which one table in a database has a foreign key that refers to a primary key in another table in the database

Question 14

Referential integrity

Answer 14

Property of a database that does not contain any values of a foreign key that are not matched to the corresponding primary key

Question 15

Index

Answer 15

Data structure built from one or more columns in a database table to speed up searching for data

Question 16

E-R model/diagram

Answer 16

Entity - Relationship
Graphical representation of a database and the relationship between the entities

Question 17

Normalisation

Answer 17

Process of organising data to be stored in a database into two or more

Question 18

Rules for normalisation (3)

Answer 18

1NF
2NF
3NF

Question 19

Normalisation

Answer 19

The process of organising data to be stored in a database into two or more tables and relationships between the tables, so that data redundancy is minimised

Question 20

1NF

Answer 20

First Normal Form

Entities do not contain repeated groups of attributes

Question 21

2NF

Answer 21

Entities are in 1NF and any non-key attributes depend on the primary key. There are no partial dependencies

Question 22

3NF

Answer 22

Third Normal Form

Entities are in 2NF and all non-key attributes are independent. The table contains no non-key dependencies

Question 23

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Answer 23

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Question 24

DBMS

Answer 24

Database Management System

System software for the definition, creation and manipulation of a database

Question 25

Data dictionary

Answer 25

Set of data that contains metadata (data about other data) for a database

Question 26

Data modelling

Answer 26

The analysis and definition of the data structures required in a database and to produce a data model

Question 27

Logical schema

Answer 27

A data model for a specific database that is independent of the DBMS used to build that database

Question 28

Access rights

Answer 28

Permissions given to database users to access, modify or delete data

Question 29

Developer interface

Answer 29

Feature of a DBMS that provides developers with the commands required for definition, creation and manipulation of a database

Question 30

SQL

Answer 30

Structured Query Language

The standard query language used with relation databases for data definition and data modification

Question 31

Query processor

Answer 31

Feature of a DBMS that processes and executes queries written in SQL