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GCSE Computer Science AQA > tag > Flashcards

tag Flashcards

1
Q

What are the data types to choose from when creating database fields?

A

⚫️integer
⚫️float
⚫️date / time /Datetime
⚫️Char (FIXED length up to 8,000 characters)
⚫️Varchar (variable length string up to 8,000 characters )
⚫️Text (variable length string up to 2GB)
⚫️autonumber

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2
Q

What are flat file databases?

A

Stores sa single table of data inside a single text file

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3
Q

What are primary keys ?

A

A field that stores unique data for each record in a table.

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4
Q

What are some flat file database issues ?

A

🔵inconsistencies in the data , making it hard to search or sort the data
🔵redundant data, so the databases use more storage/memory than needed

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5
Q

What is a ‘flat file database “?

A

A database that has all the data stored in one table.
▪️Each record is identified as a new line
▪️flat file databases are often stored using a CSV (comma separated values )format
▪️each field is separated by a comma

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6
Q

What are relational databases ?

A

Contain multiple tables , each table is known as a relation. Each table has links to others known as relationships

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7
Q

What is a foreign key?

A

A field in a table that references the primary key of another table.

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8
Q

What is SQL?

A

Structured query language
The language allows you to create , query, update and delete data to and from databases

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9
Q

Write an SQL query to output all the first names of members and their memberID, who are male

A
  • all normal PSEUDOCODE arithmetic and operational comparatives can be used
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10
Q

How do you select all the fields within a table to output

A

SELECT *

Wildcard

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11
Q

Write an SQL query to find all the fields of dogs that are older than four (including those that are 4) and whose colour contains the letter ‘B’

A
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12
Q

Sort this array called members into ascending order of town , up outputting the first name and memberID

A
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13
Q

Change the age of Molly from 5 to 6

A
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14
Q

Delete all the black spaniels from the table

A
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15
Q

Select the owner and dog names for all the four year old dogs
(Multiple tables )

A
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16
Q

Why are databases used?

A

They are used to store large amounts of data.
They make retrieving information easy and efficient

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17
Q

What are some advantages of flat file databases ?

A

All data in one table , so easier to set up and understand

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18
Q

What are some advantages of relational databases ?

A

🔵data is only stored in one place and then referenced. This means that to input , update or delete pieces of data, it only has to be done in one place which can prevent inconsistencies
🔵only storing the same price of dat once will also save storage space
🔵relational databases can be more secure , some tables can be made more confidential so only some users can see certain data (helps companies meet data protection laws)

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19
Q

What is a data redundancy?

A

Having the same piece of data stored in multiple places

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20
Q

How do you insert a full record into a table ?

A
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21
Q

How would insert bits of a record into a table ?

A
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22
Q

What is a record ?

A

The row of a table

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23
Q

What is a field ?

A

Columns of the table

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24
Q

How do relational databases eliminate data inconsistencies?

A

Since the data only has to be entered once, and can be referenced through other tables, there is less likely to be any inconsistencies such as spelling mistakes made when entering data in. This will reduce the amount of errors made when making queries

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25
Q

How do relational databases eliminate data redundancy?

A

Since the data can be referenced from other tables using foreign keys, the same pieces of data do not have to be repeated and stored in multiple places, there are no longer pieces of data that are being repeated unnecessarily

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26
Q

What is a computer system?

A

Two or more computers , that are CONNECTED together that are able to exchange data with each other. Allowing software and hardware to be shared.

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27
Q

What are the advantages of networks?

A

🟢communication eg: emails & text messages
🟢file sharing , eg: stored centrally and worked upon centrally
🟢hardware sharing , eg printers , making it more cost effective
🟢user account allow you to log in from any device
🟢installing software centrally , takes less time

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28
Q

What are some disadvantages of networks?

A

🟣expensive to set up as a lot of hardware is required. eg: NIC cards, switched , cables
🟣vulnerable to hacking and malware which can spread to networked computers
🟣hard to maintain and install , may require employing a specialist

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29
Q

Describe a PAN

A

Personal area network:
- very short range(few meters)
- cantered around 1 user
A network that is spread over a very small area used to connect personal devices
🟡don’t require additional hardware, can used them on the move
🟡often wireless technology eg: Bluetooth

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30
Q

Describe a LAN

A

Local area network
🟡small geographical area located on a single site
🟡wired or wireless
🟡owned an maintained by the organisation

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31
Q

Describe a WAN

A

Wide area network
🟡A combination of LANs in different geographical locations
🟡expensive as they need to hire infrastructure
🟡under collected or distributed ownership

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32
Q

What is a WLAN?

A

A wireless local area network

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33
Q

What is a wireless network?

A

A network that connect computers to a network through electromagnetic ☢️ radiation

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34
Q

What is a wired network?

A

Makes use of physical wire to connect computers to the network

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35
Q

Advantages wireless 🟢networks:

A

🟢Wireless are cheaper to set up.
🟢Wireless also requires less information and installation is automatic.
🟢wireless can add people more easily

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36
Q

Advantages of wired networks🔴

A

🔴wired have a larger transmission speed, higher bandwidth, more reliable
🔴wired are more secured. As physical connection is needed to intercept data
🔴wired have no interference from other Wireless networks or physical obstructions like walls

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37
Q

What is a NIC?

A

Network interface card, a piece of hardware inside a device that allows it to be connected to devices

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38
Q

What is a WAP?

A

Wireless access point
Needed in wireless networks
Basically a switch needed to connect devices wirelessly

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39
Q

What are switches?

A

Used to connect devices within a LAN to form a network
Device can access the switch simultaneously

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40
Q

What are routers?

A

Transmit data between different networks
Used to connect to the internet

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41
Q

Compare fibre optic cables and copper cables

A

Fibre: transmits dat as light.
More expensive but higher bandwidth
No interference and very large distance

Copper :
cheaper but have lower bandwidth

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42
Q

Describe a star topology

A

All devices are connected to a central switch or server, controlling the network. Can be wired or wireless

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43
Q

What is a node?

A

A device connected to a network

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44
Q

Star network pros and cons

A

✅if a device fails the network is unaffected
✅fewer data collisions as all devices can transmit data at the same time
✅easier to add devices
✅packets only sent to intended devices
❌expensive as it requires a switch and other hardware
❌problem with switch then the whole network is affected

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45
Q

Describe a bus network

A

Use a single ‘backbone ‘ cable to connect all devices.
Two terminator at the end to stop data reflections (interference)

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46
Q

Pros and cons of Bus networks

A

✅if one device fails the network remains unaffected
✅cheap to set up and maintain
✅not dependant on a switch
❌frequent data collisions slowing the network down
❌unsuitable for large networks as too many data collisions
❌network fails if the backbone cable is broken

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47
Q

Define network protocols

A

A set of rules that determine how devices communicate the transmission of data across a network

48
Q

Describe Ethernet

A

🔌A family of protocols
🔌 manages data transfer for wired LANs

49
Q

Describe HTTP

A

Hyper text transfer protocol
Used by web browsers to access websites / communicate with web servers .

50
Q

Describe HTTPS

A

Hyper text transfer protocol secure
A more secure version of HTTP, as it uses encryption . The web browser will check the web servers security certificate and ensure it is legitimate. This means that it is not possible to eavesdrop

51
Q

Describe FTP

A

File transfer protocol
Used to access , edit and move files between devices on a network, other devices
eg: to access files on a server from a client computer

52
Q

What does IMAP do?

A

IMAP- internet message access protocol:
Retrieves emails from a server

53
Q

What is TCP and how does it operate

A

Transport control protocol
Splits data into numbered packets to be sent over a network

54
Q

What is UDP and how does it operate?

A

User diagram protocol
Splits data into packets to be sent over a network, without numbering them

55
Q

Describe the differences between UDP and TCP

A

TCP is more reliable
UDP is more faster and efficient used for live video streaming

56
Q

Describe Wi-Fi

A

🔴A family of related protocols
🔴wireless data transfer on WLANs(wireless lAN)

57
Q

Describe IP and it’s purpose

A

Internet protocol,
🟣give them an IP address ,
🟣used to route the journey for packets by according to traffic

Responsible for packet switching
An IP adresss is a number code gIven to every device in the network

58
Q

What is the 4 layer TCP/IP model?

A

Application layer
Transport layer
Internet layer
Link layer

59
Q

What does the application layer do , and what are some examples?

A

Network applications like web browsers or email programs operate

Eg: HTTP, HTTPS,FTP,SMTP.IMTP

60
Q

What does the transport layer do, and what are some examples?

A

🔵sets up communication between 2 hosts
🔵make the size of packets
Eg:TCP,UDP

61
Q

What does the internet layer do, and what are some examples?

A

🔵addresses and packages the data for transmission
🔵routes the packets across the network

Eg: IP

62
Q

What is the link layer, and what are some examples?

A

Passing data over a physical network, data sent as electrical signals over cables , wireless and other hardware
🔵network hardware is located

63
Q

What is authentication, when would it be used?

A

🟣takes one or more specific data from a user
🟣only allows access to the system if credentials are valid
Preventing unauthorised access

eg: username and password

64
Q

What is encryption and when would it be used?

A

🔢the process of disguising a message so that it cannot be understood by anyone but its intended recipient
Eg: ceaser cipher, web browsers

65
Q

What is firewall , and when is it used?

A

🔥 acts as a barrier
🔥 Examines all packets entering and leaving
🔥 identifying potential threats from packets using security rules and blocking unwanted data

Software or hardware

66
Q

What is MAC address filtering and when is it used?

A

🔵takes a MAC address for each device
🔵checks to see if it is in the list of allowed , and on that basis gives it permission to connect to the system

67
Q

What is the purpose of a terminator?

A

Absorbs signals and stops data reflecting back along the bus

68
Q

Compare bus and star

A

🚎 isn’t reliant on central switch/server, ⭐️ will completely fail if central device stops working
🚎 less cabling (no switch) and so are cheaper than a ⭐️

⭐️ all devices can access the switch simultaneously, so there are no data collisions, 🚎 data collisions are common

69
Q

What does SMTP do?

A

Simple mail transfer protocol:
Sends emails to a server

70
Q

What is an IP address?

A

Identifies devices on the internet
Used by routers to direct the packets to their location

71
Q

When is UDP deemed better ?

A

🟡does not establish a connection between the two devices, making transmission quick
🟡does not require retransmission of lost/corrupt packet, making transmission quick

72
Q

Why is network security important?

A

🟠prevent cyber attacks(targeting specifics)
🟠prevent unauthorised access
🟠protects data and programs against damage

73
Q

what is malware?

A

malicious/harmful software, that is designed to cause harm or gain unauthorised access computer system

An umbrella term used to refer to a variety of forms of hostile or intrusive software.

74
Q

What are some threats to a computer system

A
  • social engineering
  • malware
75
Q

What is social engineering ?

A

a way of gaining illegal access to data or networks by influencing people (normally employees or large companies)

The art of manipulating people so that they give up confidential information

76
Q

what are some forms of social engineering?

A
  • blagging
  • pharming
  • phishing
  • shouldering
77
Q

what are some typical actions of malware?

A
  • deleting or modifying files
  • locking files (ransomware encrypting all the files)
  • unwanted adverts
  • mo
78
Q

What is Pharming?

A

redirects the user from a websites’s traffic to a fake website , in hope to gain personal information , to access their genuine account

79
Q

How could you prevent pharming?

A
  • anti-malware software , up to date
  • internet browsers using web filters
    *not clicking or links or attachments from unknown users
80
Q

What Phishing?

A

A technique if fraudulently obtaining private information, often using email or SMS

emails are sent to the user claiming to be from well known business, asking for bank details

81
Q

How to prevent phishing?

A
  • emails have anti-phishing features
  • you can spot bad grammar , or will ask to redirect to a link
82
Q

What is shouldering?

A

looking over someone’s shoulder and watching and observing their activity /private information (pin details)

83
Q

how can you reduce the risk of shouldering?

A

being discrete (covering the keypad when you enter the pin)
some softwares output astreiks instead of the symbol typed , on the screen

84
Q

What is Blagging ? (Pretexting)

A

The act of creating and using an invented scenario to engage a targeted victim in a manner that will increase the chance the victim will divulge information or perform actions that would be unlikely in ordinary circumstances.

85
Q

how could you prevent blagging?

A

reduce the risk by using using security measures that cannot be given away,
eg: biometrics

86
Q

what is penetration testing?

A

organisations employing specialists to stimulate potential attacks to their system, allowing them to identify their weaknesses in cyber security

The process of attempting to gain access to resources without knowledge of usernames, passwords and other normal means of access.

87
Q

What is the difference between white and black penentration testing ?

A

white: when the person or team testing the system has knowledge of possibly basic credentials for the target system, stimulating an attack from inside the system (a malicious insider)

black: when the person of team testing the system has no knowledge of any credentials for the target system, stimulating an attack from outside the system (an external attack)

88
Q

what are the different types of malware?

A
  • trojan
  • worms
  • spyware
  • ransomeware
  • viruses
  • adware
89
Q

what is a trojan?

A

appears to be a piece of harmless legitimate piece of software, often given away for free, that contains malicious code hidden inside. *software must be installed by the user

90
Q

what is spyware?

A

collects the data from one computer system and then sends the details to another person without the user being aware.

data being sent could be thing the user typed, or the sites that are visited, or even where the user is clicking on their screen. Spyware that records what is being typed is known as a keylogger. Keyloggers attempt to find out usernames and passwords by collecting everything that is entered into the system, which allows the hacker to search for personal data.

91
Q

What are viruses?

A

programs that are activated by opening infected files
viruses attach themselves (by copying themselves) to certain files. Users then spread them by copying infected files

*replicates by itself

92
Q

what are worms?

A

a computer program that replicates by itself without any user help, can spread rapidly within a network

93
Q

What is an anti-virus software?

A

a database of viruses. When opening a file or installing a program .If the virus is similar to the one in the database, it will warn the user. That virus is then quarantined or removed.

94
Q

What is adware?

A

legal, in extreme cases ad pop ups that do not go away. (can be solved with ani-virus software)

95
Q

What is ransomeware ?

A

when files will be encrypted and in order to recieve a decrypting key, the hackr will demand a certain amount of money.
probably from suscpitious attachtments.

96
Q

How can removable hardware also a cyber threat?

A

if attcahed to a computer on a network ,all the the comuters could get the virus

97
Q

How is unpatched software a cyber secrutity threat?

A

unpatched sotware= not up to date software and so is more sucesptible to cyber attacks.
‘patching’ updates or fixes a problem or adds new features

reduces vunerability
More outadated software is more easily exploited

98
Q

How do orgainsations keep their networks safe from threats?

A
  • encryption, to prevent wire tapping or packet sniffing
  • anti-malware software
  • firewalls
  • user access levels, stops attacks from within the organisation
  • automatic software updates
  • MAC Address filtering
    *penetration testing (white & black) to find weaknesses and correct
    *strong, regularly changed passwords, against automated software.
99
Q

Describe encryption

A

data translated into cipher text, with the correct key to decipher, data can now be sent over a network securly

100
Q

Describe Firewalls

A

examines all the data leaving and enetring the netwoek, can be software or hardware

101
Q

Describe user access levels, prevnting threats

A

pwople with higher access levels have more access to senetive data , the UAL limits the amount of people who have accesss to the sensitive information.
*Helps prevent attacks from within the organisation

102
Q

Describe MAC filtering

A

makes sure that the only people on the network are trusted employees.
It checks the unique MAC address of each devices that tries to connect to the network, and only allows certain devices to join.

103
Q

What are some types of security measures ?

A
  • email confirmation
  • biometrics
  • CAPTCHA
  • passwords
    *automatic software updates
104
Q

Biometrics

A

✓secure (cannot be given away or manipualted)
✓convienient(don’t have to remeber
X more expensive, needs special hardware

105
Q

CAPTCHA

completly automated public turning ( to tell) computers and humans apart

A

✓prevents programs from automatically doing things (creating user accounts)

106
Q

Whats wrong with putting many security measures in at a time?

A

prevents normal users from being able to use the network easily

107
Q

What is ‘cyber security’?

A

The processes , practices and technologies designed to protect networks, computers, programs and data from attack, damage or unauthorised access

108
Q

Describe a binary search

A
  1. Find the middle item in the ordered list
  2. If this is the item you’ve been looking for, then stop the search, you’ve found it !
  3. If no then compare the item you are looking for to the middle item
    If it comes before the middle item , get rid of the second half of the list (including the middle item)
    If it comes after the middle item, then get rid of the first half of the list (including the middle item)
  4. Repay these steps until you have found the item
109
Q

Describe a linear search

A
  1. Look at the first item in the unordered list
  2. If this is the item you are looking for, then stop the search as the item has been found
  3. If not then look at the next item in the list
  4. Repeat until you have found the item you were looking for, or until you’ve checked every item
110
Q

Compare a linear and a binary search

A
111
Q

Describe a bubble sort

A
  1. Look at the first two items in the list
  2. If they are in the right order then do not have to do anything
    If they are in the wrong order then swap them
  3. Move onto the next pair of items (2nd and 3rd entries) and repeat step 2
  4. Repeat step 3 until you get to the end of a list, 1 row = 1 pass
  5. Repeat steps 1-4 until there are no swaps in a pass
112
Q

Describe a merge sort

A
  1. Split the list into half (the smaller lists are called sun lists)
    *second sub list starts at the middle item
  2. Keep repeating step 1 on each sub-list , until all the lists only contain one item
  3. Merge pairs of sub-lists so that each sub list twice as many items.
    Each time you merge the sub lists, sort the items into the right order
  4. Repeat step 3 until you have merged all the sub lists together
113
Q

Compare a merge sort and a bubble sort

A
114
Q

Bubble sort pseudocode

A
115
Q

Binary search

A
116
Q

Linear search

A

GCSE Computer Science AQA (13 decks)

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