COSC203 - PART |

Question 1

A database is

Answer 1

an integrated collection of data

Question 2

A DBMS is

Answer 2

a system that allows you to access and manage a database, e.g. MySQL Workbench

Question 3

Application program

Answer 3

A program that provides access to the database by sending queries and requests for data to the DBMS

Question 4

Data modelling is the _____ in designing a database

Answer 4

first step

Question 5

A data model is a _______ that can be used to describe the structure of a database.

Answer 5

a collection of concepts

Question 6

This describes the collection of metadata that describes the logical view of a database

Answer 6

Database schema

Question 7

This technique models the data in a high level way

Answer 7

Conceptual data modelling

Question 8

This is a popular high level diagram

Answer 8

Entity Relationship Model

Question 9

An entity is

Answer 9

A thing in the real world with independent existence

Question 10

A collection of entities with the same attributes is called an…

Answer 10

Entity type

Question 11

These are the properties of an entity

Answer 11

Attributes

Question 12

A ____ exists whenever an attribute of one entity type refers to another entity type

Answer 12

relationship

Question 13

A weak entity has ______ of its own

Answer 13

no attributes

Question 14

Why would somebody allow null values in their schema?

Answer 14

To allow the users to have the option to not share private information

Question 15

A ________ is a collection of relations

Answer 15

relational database

Question 16

Constraints are restrictions on…

Answer 16

the actual values in the database state

Question 17

Constraints are derived from…

Answer 17

rules in the mini world that the database represents

Question 18

This type of constraint specifies that each value must be atomic from the domain dom(A)

Answer 18

Domain constraint

Question 19

This type of constraint has two types of keys

Answer 19

Key constraints

Question 20

A relation schema may have more than one of these

Answer 20

key constraints

Question 21

If there is a key constraint, then primary values can’t be what?

Answer 21

NULL

Question 22

T/F: NULL values can be unique

Answer 22

False

Question 23

This type of constraint is annoying as hell to delete

Answer 23

Foreign key

Question 24

Reflexivity, augmentation, transitivity, are all part of…

Answer 24

Armstrong’s axioms

Question 25

"As long as Y is a subset of X, then X determines Y" refers to which axiom?

Answer 25

Reflexivity

Question 26

"If X determines Y, then we can add the same attribute on both the LHS and RHS" refers to which axiom?

Answer 26

Augmentation

Question 27

"If X determines Y, and Y determines Z, then we can have X determine Z" refers to which axiom?

Answer 27

Transitivity

Question 28

Anomalies are caused by...

Answer 28

bad schema design in general

Question 29

Anomalies are removed by _______

Answer 29

replacing the schema

Question 30

This breaks down a relation schema into a set of relation schemas to remove redundancy, anomalies, and inconsistencies

Answer 30

Decomposition

Question 31

Which process aims to avoid insertion, deletion, and update anomalies?

Answer 31

Normalisation

Question 32

"All attribute values must be atomic, and no multi-valued composite attributes, or nested relations are allowed" refers to which normalisation?

Answer 32

1NF

Question 33

Which normalisation allows full and partial functional dependency?

Answer 33

2NF

Question 34

Removing nonprime attributes that are transitively dependent on the primary key attribute(s) and placing them in a new relation is part of which normalisation process?

Answer 34

3NF

Question 35

For any FD X->A where X is not a superkey, remove A for the original relation and then create a new relation containing both X and A refers to?

Answer 35

Boyce-Codd Normal Form

Question 36

The ____ the normal form, the _____ the relaion.

Answer 36

higher, smaller

Question 37

TINYINT, SMALLINT, BIGINT is a _____ data type

Answer 37

numeric

Question 38

A string can be defined in a database by using

Answer 38

VARCHAR(size)

Question 39

NOT NULL and CHECK are _____ constraints

Answer 39

Attribute

Question 40

PRIMARY KEY and FOREIGN KEY are ____ constraints

Answer 40

integrity

Question 41

What does % mean in the context of a database query?

Answer 41

% means any number of characters

Question 42

SUM, MIN, MAX, AVG, COUNT and COUNT DISTINCT are what type of functions?

Answer 42

Aggregation functions

Question 43

The _______ clause allows to define a subset of values of a particular field and to apply an aggregate function to the subsets

Answer 43

GROUP BY

Question 44

If a field is unknown but we need to query it, which operator can we use?

Answer 44

IS NULL