System design and Implementation

1. SYSTEM DESIGN AND
IMPLEMENTATION
By :PURVI GAUTAM

2. PROCESS OF DESIGN
 System design is the process of designing the
elements of a system such as the architecture,
modules and components, the different
interfaces of those components and the data
that goes through that system.
 System Analysis is the process that
decomposes a system into its component
pieces for the purpose of defining how well
those components interact to accomplish the
set requirements.

3. ELEMENTS OF SYSTEM
 Architecture - This is the conceptual model that defines the
structure, behavior and more views of a system. We can use
flowcharts to represent and illustrate the architecture.
 Modules - This are components that handle one specific
tasks in a system. A combination of the modules make up the
system.
 Components - This provides a particular function or group
of related functions. They are made up of modules.
 Interfaces - This is the shared boundary across which the
components of a the system exchange information and relate.
 Data - This the management of the information and data
flow.

4. PROCESS OF DESIGN
 Process Design (or Process Mapping) is a method for
ensuring an efficient, maintainable and easily
upgradeable software solution is found for your business
process. It is comprised of: a relationship map; a cross
functional process map; and a flow chart.
INPUTS:
 System design takes the following inputs −
 Statement of work
 Requirement determination plan
 Current situation analysis
 Proposed system requirements including a conceptual data
model, modified DFDs, and Metadata (data about data).

5. TYPES OF SYSTEM DESIGN
 Logical design pertains to an abstract representation
of the data flow, inputs, and outputs of the system. It
describes the inputs (sources), outputs (destinations),
databases (data stores), procedures (data flows) all in
a format that meets the user requirements.
 For example, the logical design for a relational
DBMS includes the specifications for the relations
(tables), relationships, and constraints (i.e., domain
definitions, data validations, and security views).
 A logical design is a conceptual, abstract design..
The process of logical design involves arranging data
into a series of logical relationships called entities and
attributes.

6. PHYSICAL DESIGN
 A physical design focuses on specific
solutions explaining how they are assembled
or configured.
 It focuses on how data is entered into a
system, verified, processed, and displayed
as output. It produces the working system by
defining the design specification that specifies
exactly what the candidate system does. It is
concerned with user interface design, process
design, and data design.

7. CONTD..
 Physical design represents the physical entities
of your software system. Determining how a
software system is packaged into its
deployable units is a physical design issue.
Determining which classes belong in which
deployable units is also a physical design
issue.
 For example, you can abbreviate the column
name that identifies employees,
EMPLOYEE_NUMBER, to EMPNO.

8. COMPARISON USING AN EXAMPLE

9. PHYSICAL
 Physical design is where you translate the
expected schemas into actual database structures.
At this time, you have to map:
 Entities to Tables
 Relationships to Foreign Keys
 Attributes to Columns
 Primary Unique Identifiers to the Primary Key
 Unique Identifiers to Unique Keys

10. Design methodology
 A methodology is also defined as follows " A method
describes the activities involved in defining, building,
and implementing a system; a method is a framework.
 Since a method is a logical process for constructing systems
(process), it is known as a metaprocess (a process for
modeling processes).
 Design methodology refers to the development of a
system or method for a unique situation.Today, the term
is most often applied to technological fields in reference to
web design, software or information systems design.

A recommended collection of phases; procedures; rules;
techniques; tools; documentation; management, and
training to improve the quality of a software
development effort.

11. Contd..
 Improve productivity of analysis and
programmers.
 Improve documentation and subsequent
maintenance and enhancements.
 Improve communication among the user,
analyst & designeer.
 Standarize approach to analysis and design.

12. Structured design
 It is a data flow based methodology .
 The approach begins with a system
specification that identifies inputs and
outputs ,describes functional aspects of the
system.
 Ex : DFD,ER diagram
 From the DFD the next step in the definition
of the modules and their relationship to one
another in a form is called structure chart
using data dictionary.

13. Contd…
System specification DFD DATA DICTN
STRUCTURE
PROCESS
INFORMATION
PROCEED

14. FORMS DESIGN
 The data provide the basis for information
system.Without data there is no system ,but
data must be provided in the right form for
input.
 The form is a tool with a message;it is the
physical carrier of data – of information .
 A printed form is generally classified by what
it does in the system .there are three primary
classfication : action , memory and report
forms.

15. Classification
 Action: orders,goes from
one place to another.
 Memory: represents
data,control details.
 Report:details that need
attention,decision
making , picture of
project.
 Example : application
form,purchase order.
 Journal sheet , purchase
record, stock ledger.
 Balance sheet,operating
statement , profit & loss

16. Requirements of form design
 Identification of wording.
 Maximum readability and use.
 Physical factors.
 Order of data items.
 Ease of data entry.
 Size and arrangement.
 Use of instructions.
 Efficiency considerations.
 Type of report.

17. Types of forms
 Flat form: it is a single copy form prepared on
a paper. For additional copies of the
original,carbon papers are inserted between
copies.
 It is a simplest and inexpensive form to
design ,print, which uses less volume.

18. Unit set form
 These are papers with one time carbons
interleaved into unit sets for either
handwritten or machine use.
 Carbons may be either blue or black
,standard medium intensity .Generally , blue
carbons are best for handwritten forms while
black carbons are best for machine use.

19. Continuous forms
 These multiple unit forms joined in a
continuous strip between each pair of forms.
 It is less expensive method for large volume
use.

20. INPUT DESIGN & OUTPUT DESIGN
 In an information system , input is the raw data that
is processed to produce output. During the input
design ,the developers must consider the input
devices such as PC,MICR OMR.
 Well designed input forms have following properties:
a. It should serve specific purpose effectively such as
storing , recording and retrieving information.
b. It ensures proper completion with accuracy.
c. It should be easy to fill and straightforward.
d. It should focus on user’s attention ,simplicity.

21. OUTPUT DESIGN
 The design of output is the most important task of
any system. During output design , developers
identify the type of outputs needed, consider
necessary output controls.
 Objectives :
 To develop output design that serves the intended
purpose and eliminates unwated output.
 To develop the output design meets the end users
requirements.
 To deliver appropriate quantity of output.
 To make the output available on time for making
good decisions.

22. Test plan
 The test plan is a base of every software
testing .it is the most crucial activity which
ensures availability of all lists of planned
activities in an appropriate sequence.
 A test plan is detailed document which
describes software testing areas and
activities. It outlines the test strategy ,
objectives ,test schedule, required resources
,test estimation and test deliverables.

23. Contd..
 Programmers usually do a better job in unit
testing because they are expected to
document and report on the method and
extent of their testing .
 Users are involved , which means
communication is improved between users
and the designer group.
 Programmers are involved when they aware
of user problems and expectations.

24. ACTIVITY NETWORK FOR SYSTEM
TESTING
 Prepare test plan
 Specify condition for user acceptance testing
 Prepare test data for program testing
 Prepare test data for transaction path testing
 Plan user training
 Compile programs
 Prepare job performance aids
 Prepare operational documents

25. Prepare a test plan
 Outputs expected from the system
 Criteria for evaluating outputs
 A volume of test data
 Procedure for using test data
 Personnel and training requirements

26. Specify condition for user
testing
 Planning for user acceptance testing calls for
the analyst and the user to agree on the
conditions for the test.
 Many of these conditions may be derived
from the test plan.
 The start and termination dates for the test
should also be specified in advance.

27. Prepare test data for
program testing
 Test data prepared and documented to
ensure that all aspects of the program are
properly tested.
 After the testing ,the data are filed for future
reference.

28. Transaction path testing
 This activity develop the data required for
testing every condition and transaction to be
introduced into the system.
 The test verifies that the test are virtually
comparable to live data used after
conversion.

29. Plan user training
 The system group has the time available to
spend on training while the programs are
being written.
 Initiating a user training program gives the
systems group a clearer image of the user’s
interest in the new system .
 A trained user participates more effectively in
system testing.