Systems analysis and design Flashcards
What are you doing when you are designing how data will be entered into the system?
Designing data entry forms
ICT
Investigation Methods
What are the advantages of looking at the current systems documantation?
Could save time with copies of previous analysis
Can see existing inputs, outputs and processes
Allows analyst to predict the system size required by looking at the amount of data that needs to be handled
ICT
What is this?
One-one question and answer session between system analyst and a member of staff
Analysis - researching and existing system a description of Interviews
ICT
Data validation checks
What is this?
Makes sure that data in one field is consistent with data in another field
Consistency check
ICT
Systems
Documantation and Evaluation
• Technical documentation - this is for people who may need to modify or develop the system further at a later stage
What does it contain? (7 things):
Contains: • Program flowcharts • Code listings • File / database structures • Details of validation • Error messages and meaning • Hardware and software requirements • System flowcharts
ICT
System Developmen
Describe 4 tasks that need to be done during the system development stage
I. Creating file structure to store data: • setting up tables • specifying field names • data types • field length II. Creating validation rules/checks: • in database tables for each field where it is needed III. Creating input methods: • data entry forms • creating menu systems IV. Creating output formats: • both printed and on screen
ICT
Systems
Documantation and Evaluation
What can lead to: Changes to hardware because of: • Feedback from users • Availability of new hardware • Changes within company Changes to software because of: • Feedback from users • Changes in legislation • Changes in company structure
The changes that evaluation might lead to
ICT
Investigation Methods
What are the advantages of using Observations?
Analyst can see exactly what works well and not so well
Not expensive as no one is taken away from their work
ICT
Changeover to a new system
Describe,and give advantages and disadvantages for the method of changeover called Phased
Description - When parts of the system are introduced at different times to make sure they work
Advantages - The individual parts can be fixed if any bugs occur without having to take down the entire system
Disadvantages - Can take a while as each new part has to be tested before the next can be added
ICT
Data validation checks
what is this?
Checks that the correct number of characters has been entered
Length check
ICT
Systems
Documantation and Evaluation
User information is for people who are going to use the computer system. What 7 things are contained within it?
- The purpose of the system
- How to use the system to add/delete/change data
- How to load/save/print
- What hardware is required to run the system
- Common error and what to do about them
- Tutorials
- On-line help features
ICT
What is system development?
The process of building the system
ICT
Investigation Methods
What are the disadvantages of using interviews?
Interviews take far longer than questionnaires
Expensive as interviewees need to be taken from their work
Answers may not be honest as interviewees cannot be anonymous
Interviewees might answers what they think is expected
What are these examples of? • Observation • Questionnaires • Interviews • Looking at existing paperwork
Research methods for analysis - researching an existing system
ICT - what provides this?
An overview of how a system works and helps identify
problems with the existing system
Hardware and software needed for the new system
Information requirements for the new system
What a data flow diagram provides
ICT
Data validation checks
What is this?
• When data is entered twice, and is compared before letting the user know if there are any differences. This is most commonly used when setting up an account online, to make sure you don’t accidentally press a key by mistake when entering a password
Double entry
For analysis - researching and existing system, how would you describe;
Looking at existing paperwork
Analyst looks at existing doecumentation – can see what is stored, how it is stored, presented etc.
ICT
Investigation Methods
What are these disadvantages of?
Very time consuming to look through all existing documents
Very expensive as the analyst will need to be paid
Time could be wasted if existing documentation is not relevant to the new system
Looking at the current systems documentation
ICT
Investigation Methods:
What are these advantages of?
Analyst can see exactly what works well and not so well
Not expensive as no one is taken away from their work
Using observations
ICT
Data validation checks
what is this?
Makes sure that data is in a specific format
Format check
What features should a data capture form have? (11 items)
A heading so it is clear what the form is for On screen help Clear where the answers should go Automatic validation Character boxes for names etc. (one character per box) Text boxes for answers Sufficient space for answers Drop down boxes Tick boxes for choices Clear fonts/colours Control boxes e.g. submit
ICT
Investigation Methods
What are these disadvantages of?
People often don’t complete or return them
Unclear questions can’t be explained
You may get incorrect data from misunderstood questions
It is hard to ask specific or very technical questions
Using questionnaires
ICT
Data validation checks:
Describe double entry and visual checks
- Double entry: When data is entered twice, and is compared before letting the user know if there are any differences. This is most commonly used when setting up an account online, to make sure you don’t accidentally press a key by mistake when entering a password
- Visual check: Where the person entering the data into the system carefully compares what they have entered with the original document
For analysis - researching and existing system, how would you describe observation?
Watching staff use existing system to see exactly how it works
ICT
Data validation checks
What is this?
Where the person entering the data into the system carefully compares what they have entered with the original document
A visual check
ICT
System Development
What are these and when are they used?
-Numbers from 1 to 10-
I. Normal data - data within the range which should be accepted, e.g. 5
II. Abnormal data - data outside of the range which should be rejected, e.g. 16 or sixteen
III. Extreme data - data at either end of the scale which should be accepted, e.g. 10
Three types of data that should be used when testing a new system
ICT Changeover to a new system What are these? direct parallel phased pilot
Four methods of changeover
At what stage are these things looked at?
1) How well does it meet the user requirements identified at the Analysis stage
2) How well does the system work - speed of response / quality of output
3) How easy the system is to use
4) Are there any bugs / errors in the system that need to be fixed
Evaluation stage
What are the six steps followed when a new system is being considered/ developed?
Analysis Design Development and testing Implementation Documentation Evaluation
ICT
Investigation Methods:
What are these advantages of?
Questions can be explained if misunderstood
More complex questions can be asked giving more detailed data
Questions can be changed to suit the interviewee, e.g. director compared to employee
You will get all the data as people have to answer all the questions
Using interviews
ICT
Investigation Methods
What are these disadvantages of?
They take far longer than questionnaires
Expensive as interviewees need to be taken from their work
Answers may not be honest as interviewees cannot be anonymous
Interviewees might answers what they think is expected
Using interviews
ICT
Changeover to a new system
Describe, and give advantages and disadvantages for, the method of changeover called Pilot
Description - When the new system is only used in a part of the company until it is deemed satisfactory
Advantages - Any errors can be found and fixed before fully implementing the new system
Disadvantages - Takes a while as the system has to be tested for a while, and retested if any errors/bugs are found
Explain a range check
Performed on numbers to check they are within a certain range
