Midterm

Question 1

Typical Database Design Process

Answer 1

1. Requirement Analysis
2. Modelling
3. Create Database Schema

Question 2

What are entities described by?

Answer 2

• Entity Class
• Entity Instances
• Attributes

Question 3

Criteria for Primary Keys

Answer 3

• Short
• Numeric
• Fixed
• Unique

Question 4

SQL

Answer 4

Structured Query Language

Question 5

ERD

Answer 5

Entity Relationship Diagram

Question 6

Goals of modelling a database?

Answer 6

• Representation of information
• Describes the data to be contained
• Explain how the data interrelates

Question 7

Reasons to model:

Answer 7

• Blueprint
• Easy to understand
• Easier implementation

Question 8

Entity Instances

Answer 8

The occurance of a particular entity (in a relationship), may have many.

Question 9

Surrogate Key

Answer 9

A DBMS-supplied identifier of each row of a table. Used when a unique identifier cannot be found.

Question 10

Server

Answer 10

Software specifically designed to provide services to other applications.

Question 11

MySQL

Answer 11

A database management system (DBMS) implemented as a server.

Question 12

DBMS

Answer 12

Database management system

Question 13

Foreign Key

Answer 13

A primary key from another table which is a field in another table and provides a link between the two tables.

Question 14

Minimum Cardinality

Answer 14

Minimum amount of times an entity must participate in a relationship.

Question 15

Maximum Cardinality

Answer 15

Maximum amount of times an entity can participate in a relationship.

Question 16

Composite Key

Answer 16

Consists of more than one attribute, this happens when a single key attribute cannot uniquely identify an entity instance.

Question 17

Query

Answer 17

A statement that retrieves information.

Question 18

DATEDIFF

Answer 18

Indicates the difference between the start_date and end_date.

Formatted as: DATEDIFF(date1, date2)

Question 19

DATE

Answer 19

Contains the date only.

Formatted as: YYYY-MM-DD

Question 20

DATETIME

Answer 20

Contains both the date and time components.

Formatted as: YYYY-MM-DD hh:mm:ss

Question 21

DISTINCT

Answer 21

Retrieves unique values.

Question 22

SELECT

Answer 22

Used to select data from a database.

Question 23

Normalization

Answer 23

Orginizing data for ease of use, and to minimize redundancy.

Question 24

Parent and Child Tables

Answer 24

In a one-to-many the parent is the entity on the ‘one’ side of the relationship and the child is the many side of the relationship.

Question 25

----------------I--I

Answer 25

Mandatory - One (exactly one)

Question 26

---------------l--<

Answer 26

Mandatory - Many (one or more)

Question 27

-------------O--I

Answer 27

Optional - one (zero or one)

Question 28

------------O--<

Answer 28

Optional - Many (zero or more)

Question 29

Relationships

Answer 29

How different entities interact, usually expressed as relationship sentences.

Question 30

Identifiers

Answer 30

The primary key. Attributes that can uniquely identify entity instances.

Question 31

How are Entities Implemented?

Answer 31

As tables (entity brcomes the table name, and attributes become rows or records).

Question 32

Attributes

Answer 32

Describe the characteristics of an entity.

Question 33

Entity Class

Answer 33

A collection of entities of the same type.

Question 34

Entity

Answer 34

Something that users want to track.