"ISDD" Flashcards
insertion anomaly
cannot add info without also doing PK
database validation checks
range check restricted choice length check presence check unique check
what does css stand for
cascading style sheets
pro of using a relational database
removes anomalies
SQL
structured query language
what does it mean if you are information rich
you can access many sources of information like: TV, radio, books, news magazines and can access the www
field name from:
Dog.dogname and criteria = “Olly”
dogname
what does it mean if you are information poor
you tend to not have access to the web and probably find it difficult to access books
-these may be pensioners
modification anomaly
lots of fields may need changing instead of just one
what is an information system
an information system is a combination of hardware and software that can be searched sorted and categorized
deletion anomaly
when something is deleted then something else may also be completely deleted because that may be the only occurrence of that item
what are forms
interfaces through which you can enter information in your database
table name from:
Dog.dogname and criteria = “Olly”
Dog
whats a report
used to summarize and present data in tables in the fastest and easiest readable way possible
characteristic of a poorly designed database
insertion, modification, deletion anomalies.
a complex search
is done on two or more fields
compound key
combines more than one field to make a unique value
a simple search
is done on one field only
search criteria from:
Dog.dogname and criteria = “Olly”
and criteria = “Olly”
whats a query
a request for information from a database that matches a set of criteria
A business is setting up a new communications network. Describe two
implications of the Regulation of Investigatory Powers Act (2000) for this
business.
(Provide facilities) for public authorities (eg police/MI5/ government) to intercept electronic communications OR fit equipment to facilitate surveillance (technical services) OR pay for systems to assist with interception of electronic communications OR pay for the hardware needed to store electronic communication OR inform staff of the fact that access to communication data is subject to the RIPA.
Describe two benefits of prototyping when following a rapid application
development methodology
Allows the client to see/test/ feedback on proposed solutions OR Subsystems/specific elements can be prioritised and tested as early as possible OR A range of proposed solutions can be developed on a small scale instead of the need for full implementation
How do you figure out the range of numbers that can be stored with a set number of bits.
use formula:
2^n - 1
and range is 0 - the result of that calculation above
The more processors present….
The more processors present, the greater the number of tasks that can be processed simultaneously.
what is parallel processing
Parallel computing is when several processors process tasks simultaneously
the data bus is uni/di directional
bi directional
the address bus is uni/bi directional
uni directional
where can the data bus go to/from
to main memory from the processor and vice versa.
where can the address bus go to/from
from the CPU to RAM.
a processing unit in a processor is also called a
core
the more cores a processor has the more
power it has to run multiple programs at the same time
this increases computer performance
the more cache memory there is, the more
data can be stored closer to the CPU
what are a few positive impacts of modern technology
heating systems, traffic control, car management systems
the four main aspects of computer hardware that allow the system to operate
the processor, the buses, the main memory and the cache memory
how can cache memory improve system performance
it stores frequently accessed instructions so it can be accessed faster
is cache memory faster accessed than RAM and backing storage?
yes
security risk associated with cookies
they monitor what you do and use your information badly or in a way you don’t want
REMINDER: when writing occurrences standard algorithm for pseudocode; make it clear that you are looking through an array.
REMINDER: when writing occurrences standard algorithm for pseudocode; make it clear that you are looking through an array.
if text is added to a vector image what effect does it have on file size?
the file size increases a little
if text is added to a bitmap image what effect does it have on file size?
the file size does not change
advantage of using open source software
it is free and can be distributed to others and other devices
what is proprietary software also known as
closed source software
disadvantage of using proprietary software
you could be restricted by the amount of copies run on devices
what is proprietary software
software that is owned by a company and licensed for a fee
M = ? A = ? R = ? E = ?
M = Mantissa A = Accuracy R = Range E = Exponent
advantages of using ASCII (2)
Only requires 1 byte per character, therefore, faster to
process;
Almost all computers understand ASCII
disadvantage of using ASCII (1)
Only has basic alphabets / limited character set
advantages of using Unicode (2)
Large character set;
Allows use of many languages;
disadvantage of using Unicode (1)
Larger storage requirements – 2 bytes, therefore slower to process.
advantages of using bitmap image(2)
Can be manipulated at the pixel level;
Simple to output as long as output device has enough memory.
disadvantages of using bitmap image(2)
Can take a lot of storage space, compression can
help;
When enlarged too much they appear “blocky” and the pixels can be seen.
some file types that support bitmap graphics
.BMP .GIF .JPEG .PDF .PICT .TIFF
Definition: Resolution
The number of pixels used to store the graphic.
Characteristics of bitmap images
Graphic is split into individual pixels;
Colour of each pixel stored individually as binary digits, (Bit depth);
Can have very high file sizes;
Editing can be done at the pixel level;
When images are enlarged they can become “jagged”.
Characteristics of vector / raster graphics
Store attributes of graphics, NOT PIXELS;
Attributes include:-Object
Start position
End position
Line thickness
Line colour
Fill colour etc.
Resolution independent, therefore can be scaled with no loss of quality;
Editing done on objects, not at pixel level;
Less storage required;
Objects can be layered over each other, retaining each object attributes.
advantages of using vector graphics(2)
Small file sizes;
When enlarged they do not lose quality.
disadvantages of using vector graphics(2)
Cannot be manipulated at the pixel level;
Can be difficult to output.
some file types that support vector graphics
PDF, EPS, PSD, AI
External Memory is aka
the Backing Storage devices
Define: Peripherals Devices
Any device attached to the computer that isn’t essential to its running
Maximum addressable memory = ?
Maximum addressable memory = 2ᵃᵈᵈʳᵉˢˢ * Data bus width
SDD: Analysis; Purpose
a general description of the purpose of the software
SDD: Analysis; Scope
the list of deliverables that will be handed over to the client, this includes: detailed design of program structure test plan and completed test data table working program results of testing evaluation report
SDD: Analysis; Boundaries
the limits of what the project will contain and assumptions are clarified
SDD: Analysis; Functional Requirements
the features that must be delivered by the system in terms of inputs, processes and outputs
SDD: Evaluation; fitness for purpose
whether the software carries out all the required functions
SDD: Evaluation; efficient use of coding constructs
reflection on whether the software is as efficient as can be by using: suitable data types or structures conditional or fixed loops arrays nested selection procedures with parameter passing
SDD: Evaluation; Usability
how intuitive the software is from a user's perspective: general user interface user prompts screen layout any help screens
SDD: Evaluation; Maintainability
how easy it is to alter the software. factors affecting this are:
readability of code
amount of modularity
SDD: Evaluation; Robustness
how well the software copes with errors during execution including:
exceptional data
incorrect data
SDD: Testing; Dry run
the process of manually working through the program to trace the values of variables
SDD: Testing; Trace tables
a simulation of the flow of execution where statements are executed step by step and the changes of variables are tracked
SDD: Testing; breakpoints
an intentional stopping of the program put in place for debugging purposes
SDD: Testing; watchpoints
a special breakpoint that stops the program when the value of an expression changes
ISDD / DDD: Analysis; end user requirements
the people who are going to be using the database and the tasks they expect to be able to do using it
ISDD / DDD: Analysis; functional requirements
processes that the system has to perform and information that the system has to contain to be able to carry out its functions. these will:
clarify the design of the database
identify the features to implement
evaluate if the system is fit for purpose after development
ISDD / DDD: Design; fitness for purpose
whether the database fulfills all the required purposes
ISDD / DDD: Design; accuracy of output
whether any data that needs to be produced from the database is accurate
what is cardinality
the number of participants in the relationship
WDD: Analysis; end-user requirements
the people who are going to be using the website and the functions they expect to be able to do using it
WDD: Analysis; functional requirements
processes that the website has to perform and display
WDD: Testing; compatibility testing
browser, device type common problems: changes in font size changes in user interface alignment issues changes in CSS style and colour scrollbar issues content overlapping broken tables
WDD: Testing; other testing that isn’t compatibility
navigational bar works, input validation, media content works
WDD: Evaluation; fitness for purpose
whether the web page fits all the required functions and contains all the needed elements
WDD: Evaluation; usability
how intuitive the software is from a user’s perspective:
general user interface
user prompts
screen layout
what is a database driven website
a web page that grabs information from a database and inserts that information into the web page each time it is loaded. if the data in the database changes, the web page connected to the database will also change automatically
