System analyst
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Is brought to review an existing system and
Methods of researching the current system
1. Observation
This involves the systems analyst walking around the organisation or business, watching how things work with his/her own eyes.
Observation allows the systems analyst to gather first-hand, unbiased information, inexpensive method.
The downside to observation is that often people won't
work the way they normally do if they know they
Methods of researching the current system
2. Interviews
• The systems analyst can interview key people at different levels (employees, managers, directors) within the system to find out how it works.
• Questions can be explained.
Methods of researching the current system
3. Questionnaires: With large groups of people, a
questionnaire is a quick and simple way to gather information.
However the information gathered is limited by the
questions set by the systems analyst (people could have a lot of useful information in their heads, but if the
questionnaire doesn’t ask the right questions, they will not be able to pass it on)
Methods of researching the current
system
4. Collecting documents
• Most businesses and organisations use documents to record information, or to communicate information (forms get filled in and passed to other offices, etc.)
The systems analyst needs to collect examples of the documents used to get an understanding of
Name of method Description Advantages Disadvantages
Observation Watching personnel using the existing system to find out exactly how it works.
• Inexpensive
• The analyst obtain reliable data
• See exactly what is being done
• People uncomfortable being watched.
• Some people will behave differently if they are being watched.
Questionnaires Involves sending out
questionnaires to customers or to work force to find out their view of the existing system.
• The questions can be answered quickly • Inexpensive
• Individuals can remain anonymous if they want. • Quick analysis of data.
• People do not return questionnaires.
• many people do not take the time to fill in questionnaires seriou sly.
• No way to clarify incomplete answers. Interviewing one to one question and
answer session between analyst and the
employee/customer
• Easier to extend questions.
• Can ask specific questions and allows the analyst to modify questions as the interview proceeds. • Very detailed
information can be gathered.
• It can be time consuming • It is relatively
expensive.
• Interviewee can’t remain anonymous
Looking at existing documents
Allows the analyst to see how the paper files are kept
• Allows information about data flow which is
impossible by any of the other methods
• See how the input/output of the system
• It can be very time consuming
Analysis
The system analyst now looks through the
information's to understand how the
Analysing the Present System
1. Collecting information from the current system.
2.Identifying the Inputs, Outputs and Processes (The system
analyst has to understand how the present system works).
3.Identifying Problems : if these problems can be fixed, the
system will work more
Analysing the Present System
4. Agreeing objectives with the customer.
5.Requirements Specification.
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analyst can begin to plan how the new system
will fix those problems.
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The system analyst specifies a list of
Analysing the Present System
6. Producing cost benefit analysis.
• What Hardware and Software Will Be Required?
• Hardware????????????
Software?????????????
Producing a data flow diagram.
Used to describe:
• He need to describe inputs, outputs and processing f the current system.
• The need to identify the problem with the current system.
• The need to identify the user and information requirements for the new system.
Designing the new system
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Design data capture forms/input forms.
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Design screen layouts.
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Design output forms and reports.
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Produce system flowcharts.
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Select validation rules.
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Select verification methods.
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Design file structure.
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Select and design of hardware.
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Select and design software.
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Produce program flowcharts.
Design the system inputs
Designing the System Inputs
To get data into a system is a two-part process:
Data must first be ‘captured’ (collected in a way that then makes it easy to input)
Data must be input into the computer
The systems analyst will select a data capture method
Paper Forms
• Forms can be simple ones with enough spaces for numbers and text to be written in.
• The data from this form will be typed into the computer. • Have a heading to make the purpose of the form clear.
• Make use of text boxes which limit the amount of information collected.
• Use character boxes for sure name , forename.
• Make use of tick boxes to make choices easier(male,female) • Make sure there are sufficient space to write answers.
• Clear fonts and clear text colors to ensure the font is easy to read.
Designing On-Screen Forms for Data Input
On screen forms should:
• Have all the necessary fields.
• Have obvious places for user input. • Use appropriate controls for each field( example text box…)
• Have easy to understand instructions (if needed).
Form Controls for on screen forms
• Textbox : used for normal text input • Buttons : to perform action
• Option / Radio Buttons: used to select an option only can be picked)
• Tick / Check Boxes: more than one can be ticked.
Designing the System Outputs
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On-screen reports (information displayed on
the monitor)
On screen reports should:
• Have all the necessary fields.
• Have fields that are the right size.
• Make good use of colors and fonts to Make the data clear
• Have easy to understand instructions (if needed).
Designing the System Outputs
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Designing printed reports: reports need to fit
a piece of printer paper.
Designing the System Processes
Designing Data and File Structures
• The type of data being stored (numbers, text, dates, etc.)
• The size of the data (how long is a typical name, etc.) • The field names to use
backing storage device and media
• How often will the data need to be accessed
• How quickly the data needs to be accessed
Designing the How the Data Will be
Processed
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system designer also needs to design the
Validation and verification
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system designer can build
in validation and verification checks into the
software that the data is entered into.
System Flow charts
• Shows how data flows through a system and how decisions are made, gives an overall view of the proposed system.
Verification
Verification is checking that data has been accurately copied from one medium to another.
There are two common ways for verification:
• Double entry: data is entered twice, the computer
compares the two entries and identifies any differences. If it does not match it generates an error, and the person will need to correct the data
Verification
2. Visual verification: to check for errors.
A person compares the original data with the data
in the computer( using printout or on screen).
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Verification does not check that data is correct
If original data is incorrect it will still be incorrect
after it has been copied accurately.
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Verification can sometimes be carried out by the
user.
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Verification will pick up errors that validation
validation
Validation is the checking that data is reasonable
or acceptable.
Example if the data falls within accepted
boundaries.
Validation does not check that data is correct.
Validation check Description Examples
Range check Checks if the data is within acceptable values.
A person age should be in the range 0 to 150
Length check Checks if the input data
contains the required number of characters
If the field is six inputting 5 will be an error
Character/type check Checks if the input data does not contain invalid characters
A person height should only contain digit
Format check Check that the data in a specific format
In the form dd/mm/yyyy
Presence check Checks if the data is actually present and has not been missed out
The field can not be left empty required field.
Consistency check Checks if fields corresponds with each other
If Mr has been typed into a field title then the gender must contain M
Check digit Looks at an extra digit which is calculated from the digits of a number then put on the end of the number
• If two digits has been transposed during input. • An incorrect digit have
been entered Example: barcode Lookup check Checks whether the data
