introduction

Question 1

what is data

Answer 1

anything that can be represented in binary

Question 2

why do we collect data

Answer 2

so that we can retrieve information and understand it

Question 3

what is data engineering

Answer 3

the process of designing and building systems that allow people to collect manage and analyse data

Question 4

what do data engineers do

Answer 4

make raw data useable for data scientists and third parties in general

Question 5

which 6 things are data engineers responsible for

Answer 5

pipelines
integration
quality
analysis
security
automation

Question 6

data pipelines

Answer 6

flows that manage and process large data sets

Question 7

data integration

Answer 7

ensuring that data from different sources is integrated seamlessly

Question 8

data quality

Answer 8

making sure the data infrastructure is reliable efficient and of high quality

Question 9

data analysis

Answer 9

analysing raw data to show trends and provide predictive models

Question 10

data security

Answer 10

protecting data against loss/theft

Question 11

automation

Answer 11

automating tasks within the data pipeline which improves efficiency

Question 12

what is a database

Answer 12

structured systems for storing retrieving and managing data

Question 13

what is raw data

Answer 13

data kept in an excel file

Question 14

how is data stored in a database

Answer 14

organised in a structured format using data models

Question 15

data model

Answer 15

defines how data will be related and stored

Question 16

what are some negatives of file processing applications

Answer 16

would have to hire a developer as they were hard to implement which is expensive
issues with optimisation performance reliability and reuse

Question 17

what is a file processing application

Answer 17

a set of files that are processed to retrieve information

Question 18

logical model

Answer 18

allows a logical representation which aids processing which can be represented graphically via an entity relationship diagram

Question 19

dbsm

Answer 19

database management system; uses the logical model to control the database and provides efficient reliable multi-user storage and access to large amounts of persistent data

Question 20

what is the difference between source code, a program, and software

Answer 20

source code; code written by developers that isn’t directly executable
program; what you get when the source code is executed
software; the entire collection of programs, libraries and related data

Question 21

ddl

Answer 21

data definition language; creates tables

Question 22

dml

Answer 22

data manipulation language; modifies tables

Question 23

what is an entity and how is it represented in an er diagram

Answer 23

an object with distinguishable attributes
rectangle

Question 24

entity set

Answer 24

a representation of entities with the same set of attributes

Question 25

what is an attribute and how is it represented in an er diagram

Answer 25

information that describes an aspect of an entity
oval

Question 26

primary key

Answer 26

unique identifier for an entitiy

Question 27

what is a derived attribute and how is it represented in an er diagram

Answer 27

an imaginary attribute not stored in the database but derived using system recourses
dashed/broken oval

Question 28

what are multi-valued attributes and how are they represented in an er model

Answer 28

attributes with more than one value
double oval

Question 29

composite attributes

Answer 29

an imaginary group of attributes not in the table that groups together existing attributes

Question 30

relation

Answer 30

a logical model for associating 2 or more entities

Question 31

what is a relationship set and how is it represented in an er model

Answer 31

a set of all relationship that can have attributes and a primary key
diamond

Question 32

degree of relationship set

Answer 32

number of different entity sets in the relationship

Question 33

one to one relationship

Answer 33

created whilst creating the table and can lead to new tables

Question 34

total participation (must)

Answer 34

for every entity in an entity set, it must relate to at least another entity in the other set

Question 35

partial participation (may)

Answer 35

not all entities have to map to another entity in the other set

Question 36

what is combined to create the subject table key

Answer 36

owner table primary key + subject table weak key

Question 37

overlap constraints

Answer 37

restrictions on the relationship between different entities, ensuring that they don’t simultaneously occupy conflicting roles

Question 38

covering constraints

Answer 38

ensures that everything is correctly classified within the appropriate categories and leaving no gaps in the er model

Question 39

what are the 2 reasons that we use ISA

Answer 39

identifies entities that participate in relationships
adds descriptive attributes to a specific subclass