this presentation is prepared by me and by friend @alina dangol. This is basically the slide related to the design of a system, how to generate forms & reports, about normal forms as well as file organization

1. System Design
BY: Alina Dangol
Lumanti Manandhar

2. Introduction To System Design
● From output of System analysis i.e requirement specification second phase i.e. system
design starts.
● It is the process of defining the architecture, components, modules, interfaces, and data
of a system to satisfy specified requirements.
● This phase focuses on the solution domain, i.e. “how to implement?”
● It is the phase where the SRS document is converted into a format that can be
implemented and decides how the system will operate.

3. System Design
Phase of detailing how a system will meet the information requirements is broken into two
sub phases:
Logical Design
➢ In logical design what is to be accomplished will be designed(DFD , ER etc)
➢ It describes the inputs (sources), outputs (destinations), databases (data stores),
procedures (data flows) all in a format that meets the user requirements.
Physical Design
➢ In physical design how to accomplish it will be designed using hardware,software etc.
➢ It is concerned with user interface design, process design, and data design.

5. Stages in the Design Process
● Analyze the situation
● Write a brief
● Research the problem
● Write a specification
● Work out possible solutions
● Select a preferred solution
● Prepare working drawings and plan ahead
● Construct a prototype
● Test and evaluate the design
● Write a report

6. Design Models
● System Implementation Model
○ Processor Model: decides how the essential model should be allocated to different
processors and how those processors should communicate with one to another.
○ Task Model : When the processes and stores have been allocated to processors, the
system designer assign processes and data stores to individual propose tasks.
● Program Implementation Model
The most common model for organizing the activity within
a single, synchronous unit is the structure chart, which
shows the hierarchical organization of modules within one task.

7. Design Process

8. Functional Design
❏ Focuses on the actions of a new or revised product, program, service or process
❏ converts the System Requirements Specification which tells what the software must do
and how to do it.
❏ Here, prototyping can be very useful in translating technical design language into an
understandable action.
The major activities performed during functional design are:
• Define Software Structure • Define Content Of System Inputs
• Design User Interfaces • Define Content Of System Outputs
• Design System Interfaces • Design System Security Controls
• Build Logical Model • Build Data Model
• Develop Functional Design • Procure Hardware And Software
• Conduct Structured Walkthroughs • Conduct Functional Design Review

9. System Design
❏ converts the user-oriented functional design into technical, computer-oriented, detailed
system design specifications.
❏ Individual software modules, routines, processes, and data structures are defined.
The major activities performed during system design are:
• Select System Architecture • Design Software Module Specifications
• Develop System Design • Develop System Test Plan
• Develop Program Specifications • Define Programming Standards
• Develop Conversion Plan • Conduct System Design Review
• Develop Integration Test Plan • Design Physical Model And Database Structure
• Conduct Structured Walkthroughs

10. Program Design
❏ produces the actual working software modules specified in the System design phase.
❏ The program specifications from the system design phase are used to design and code
the individual program modules.
The major activities performed during program design are:
• Write Programs • Conduct Unit Testing
• Generate Operational Documents • Conduct Structured Walkthroughs
• Develop Training Program • Establish Programming Environment
• Plan Transition To Operational Status

11. Fig: Schematic of System Design
Process

12. Designing Forms and Reports
What is a form?
● business document that contains some predefined data and often includes some areas
where additional data are to be filled in.
● typically based on one database record.
● Examples: A computer sign in sign out menu, An ATM transaction layout, Internet
forms for order, product information or electronic spreadsheet.
What is a report?
● business document that contains only predefined data; it is a passive document used
solely for reading or viewing.
● often contains data about multiple unrelated records in a computer file.
● Examples : invoices, weekly sales summaries by salesman, a pie chart of population by
age.

13. Common types of Business report
Report Name Description
Scheduled Report Reports produced at predefined intervals – daily, weekly or monthly- to support the
routine information needs of an organization
Key-Indicator Report Reports that provide a summary of critical information in a recurring basis
Exception Reports Reports that highlight data that are out of the normal operating range
Drill-Down Reports Reports that provide details behind the summary values on a key-indicator or
exception
report
Ad-hoc Reports Unplanned information requests in which information is gathered to support a
nonroutine decision

14. Process of Designing Forms & Reports
❖ User-focused activity
❖ Follows a prototyping approach
❖ Requirement determination
● Who will use the form or report?
● What is the purpose of the form or report?
● When is the form or report needed and used?
● Where does the form or report need to be delivered and used?
● How many people need to use or view the form or report?

15. Process of Designing Forms & Reports(cont.)
Coding sheet
● an “old” tool for designing forms and
reports usually associated with text-
based forms and reports.
Visual Basic and other development tools
● provide computer GUI form and report
generation.

16. Figure : A data input screen designed in Microsoft’s Visual Basic.NET

17. Guidelines/Process of Formatting Forms And Reports
Meaningful Title : use clear, specific titles, valid and current date
Meaningful Information : include only necessary information, with no need to modify
Balance The Layout : use adequate spacing, margins and clear labels.
Design An Easy Navigation System : show how to move forward and backward and
where we are currently (e.g. page 1 of 7).
Highlighting: notify users about the errors in data entry or processing, providing warnings
to users, drawing attention to keywords, commands,

18. Methods Of Highlighting
• Blinking And Audible Tones
• Color Differences
• Intensity Differences
• Size Differences
• Font Differences
• Underlining
• All Capital Letters

19. Color Vs No color
Benefits From Using Color: Problems from
Using Color:
• Soothes or strikes the eyes. Color pairings
may cause problems.
• Accents an uninteresting display. Resolution may
degrade
• Facilitates subtle discriminations in complex displays Color fidelity may degrade
• Emphasizes the logical organization of information Printing or conversion may not easily
translate
• Draws attention to warnings.
• Evokes more emotional reactions.

20. Guidelines for Displaying Text
Case Display text in mixed uppercase and lowercase and use conventional
punctuation
Spacing Use double spacing if space permits. If not, place a blank line between
paragraphs
Justification Left Justify test and leave a ragged right margin
Hyphenation Do not hyphenate words between line
Abbreviations Use abbreviations when they are widely understood by users and are
significantly shorter
than the full text

21. File Organization
● File organization refers to the relationship of the key of the record to the physical location of that record in the
computer file.
● Files contain computer records which can be documents or information which is stored in a certain way for later
retrieval.
● File organization refers primarily to the logical arrangement of data (which can itself be organized in a system of
records with correlation between the fields/columns) in a file system.
File organization may be either physical file or a logical file:
• A physical file is a physical unit, such as magnetic tape or a disk.
• A logical file on the other hand is a complete set of records for a specific application or purpose. It may
occupy a part of physical file or may extend over more than one physical file

22. Criteria for a good file organization
->Fast access to single record or collection of related records.
->Easy record adding/update/removal,without disrupting.
->storage efficiency.
->Redundancy as a warranty against data corruption.
Techniques of file organization:
1. Heap (unordered)
2. Sorted
->Sequential access.
->Line sequential access
->Index sequential access.
3. Direct/random/hashed access

23. 1. Heap (unordered)
● Basically these files are unordered files. It is the simplest and most basic type.
● These files consist of randomly ordered records. The records will have no particular
order.The operations we can perform on the records are insert,retrieve and delete.
● The features of the heap file or the pile file Organisation are:
1.New records can be inserted in any empty space that can accommodate them.
2.When old records are deleted, the occupied space becomes empty and available for
any new insertion.
3.If updated records grow; they may need to be relocated(moved) to a new empty
space. This needs to keep a list of empty space.

24. 1. Heap (unordered) (cont...)
Advantages
1.This is a simple file Organisation method.
2. Insertion is somehow efficient.
3. Good for bulk-loading data into a table.
4. Best if file scans are common or insertions are frequent.
Disadvantages
1.Retrieval requires a linear search and is inefficient.
2. Deletion can result in unused space/need for reorganisation.

25. Sequential access
● The records are arranged in the ascending or descending order or chronological order of a key field which may be
numeric or both. Since the records are ordered by a key field, there is no storage location identification.
● It is used in applications like payroll management where the file is to be processed in entirety, i.e. each record is
processed.
● Sequential files are normally created and stored on magnetic tape using batch processing method.
● Records are stored and accessed in a particular order sorted using a key field.
● Retrieval requires searching sequentially through the entire file record by record to the end.
● For example, of the file has records with key fields 20, 30, 40, 50, 60 and the computer is searching for a record
with key field 50, it starts at 40 upwards in its search, ignoring the first half of the set.

26. Sequential access(cont…)
Advantages:
• Simple to understand.
• Easy to maintain and organize
• Loading a record requires only the record key.
• Inexpensive I/O media and devices can be used.
• Easy to reconstruct the files.
Disadvantages:
• Entire file must be processed, to get specific information.
• Transactions must be stored and placed in sequence prior to processing.
• Data redundancy is high, as same data can be stored at different places with different keys.

27. Line sequential file organization
Line-sequential files are like sequential files, except that the records can contain only characters as data. Line
sequential files are maintained by the native byte stream files of the operating system.
In the COBOL environment, line-sequential files that are created with WRITE statements with the ADVANCING
phrase can be directed to a printer as well as to a disk.
The primary use of line sequential files (which are also known as "text files" or "ASCII files") is for display-only data.
Most PC editors, for example Notepad, produce line sequential files.
In a line sequential file, each record in the file is separated from the next by a record delimiter. The record delimiter,
which comprises the carriage return (x"0D") and the line feed (x"0A") characters, is inserted after the last non-space
character in each record. A WRITE statement removes trailing spaces from the data record and appends the record
delimiter. A READ statement removes the record delimiter and, if necessary, pads the data record (with trailing
spaces) to the record size defined by the program reading the data.

28. Example of Line Sequential organization

29. Index sequential access
● The records are stored sequentially on a direct access device i.e. magnetic disk and the data is accessible
randomly and sequentially.
● It covers the positive aspects of both sequential and direct access files.
● The type of file organization is suitable for both batch processing and online processing.
● Here, the records are organized in sequence for efficient processing of large batch jobs but an index is also used
to speed up access to the records.
● Indexing permit access to selected records without searching the entire file.

30. Index sequential access(cont…)
Advantages:
• Permits efficient and economic use of sequential processing technique when the activity rate is high.
• Permits quick access to records, in a relatively efficient way when this activity is a fraction of the work load.
Disadvantages:
• Slow retrieval, when compared to other methods.
• Does not use the storage space efficiently.
• Hardware and software used are relatively expensive.

31. Direct/random/hashed access
● Files in his type are stored in direct access storage devices such as magnetic disk, using an identifying key.
● The identifying key relates to its actual storage position in the file. The computer can directly locate the key to
find the desired record without having to search through any other record first.
● Here the records are stored randomly, hence the name random file. It uses online system where the response and
updation are fast.
● Records are stored randomly but accessed directly.
● To access a file stored randomly, a record key is used to determine where a record is stored on the storage media.
● Magnetic and optical disks allow data to be stored and accessed randomly.

32. Direct/random/hashed access(cont…)
Advantages:
● Records can be immediately accessed for updation.
● Several files can be simultaneously updated during transaction processing.
● Existing records can be amended or modified.
● Very easy to handle random enquiries.
● Most suitable for interactive online applications.
Disadvantages:
● Data may be accidentally erased or overwritten unless special precautions are taken.
● Risk of loss of accuracy and breach of security. Special backup and reconstruction procedures must be
established.
● Less efficient use of storage space.
● Expensive hardware and software are required.
● High complexity in programming.
● File updation is more difficult when compared to that of sequential method.

33. Differences

34. NORMALIZATION
● The process of converting complex data structures into simple, stable data structures.
● Normalization provides an algorithm for reducing complex data structures into simple structures.
● Process of splitting tables to reduce data redundancy and establishing relations between tables.
NEED OF NORMALIZATION
● Relations formed by the process makes the data easier to understand and manipulate.
● Provides a stable base for future database growth.
● Simplifies relations and reduces anomalies
OBJECTIVES OF NORMALIZATION
● To free a collection of relation from undesirable insertion, update and deletion.
● To move the relational model more informative to use.
● To increase the lifetime of application programs.

35. PROPERTIES OF RELATION AFTER NORMALIZATION
● No data value should be duplicate in different row or tuple.
● A value must be specified for every attribute in a tuple.
● Important information should not be accidentally lost.
● When new data / record are inserted to relation, other relation in database should not be affected
TYPES OF NORMALIZATION
● 1NF(First Normal Form)
● 2NF(Second Normal Form)
● 3NF(Third Normal Form)

36. 1NF(First Normal Form)
->A table is said to be in 1NF if it has no two rows of data repeating groups ie unique rows ,No multivalued attributes
->For a relation to be in 1NF all its attributes must be atomic
->Every non-primary key attribute must be functionally dependent on the Primary key
->First normal form enforces these criteria:
● Eliminate repeating groups in individual tables.
● Create a separate table for each set of related data.
● Identify each set of related data with a primary key

37. 2NF(Second Normal Form)
->A table is said to be 2NF if it is already in 1NF, there must not be any partial dependencies of any non key columns,
depends on the entire key.
A relation is in second normal form (2NF) if any of the following conditions apply:
▪ The primary key consists of only one attribute.
▪ No nonprimary key attributes exist in the relation .
▪ Every nonprimary key attribute is functionally dependent on the full set of primary key attributes.
Fig:Unnormalized table Fig:Normalized table in 2NF

38. 3NF(Third Normal Form)
A table is said to be in third normal form if
● it is already in 2NF and
● non key columns are not dependent on each other.
There should not be any hidden dependencies among non key columns.
So this transitive dependencies must be removed from the table.

39. Transforming ER diagrams to relations
->To compare the conceptual data model and the normalized relations developed, ER
diagram must be transformed into relational notation, normalized and then merged
with the existing normalized relations.
Steps
1. Represent entities
2. Represent relationships
3. Normalize the relations
4. Merge the relations
A short description about them is given in the next slide:

40. 1. Represent entities
● Each entity type in ER diagram becomes a relation.
● Identifier of entity type becomes primary key of relation
● Other attributes become non-primary key.
Primary key
● Value of key must uniquely identify every row in relation.
● Key should be non-redundant
Customer_ID Name Address
1824 Ram Lalitpur
2543 Shyam Nepalgunj

41. 2. Represent Relationships
● Representation of relationship depends on its nature (degree and cardinality).
● In some case, we make the primary key of one relation, foreign key of another relation.
● In other case, we create separate relation to represent relationship.
● There are many types of relationships such as follows;
2.1 Binary 1:N ( one to many) relationship
2.2 For 1:1 (one to one) relationship
2.3 M:N relationship
2.4 Unary Relationships

42. 2.1 Binary 1:N ( one to many) relationship
1:N is represented by adding primary key of entity on one side of relationship as a foreign key in
relation that is on the many side of relationship.
Customer
Order
Customer-Id Name Address
1234 Digvijay Tinkune
3265 Swopnil Maharajgunj
Order-Number Order-date Promised-date Customer-ID
234 15th July 17th July 1234
322 25th April 30th April 3265

43. 2.2 1:1 (one to one) relationship
● Add primary key of A as foreign of B
● Or Add primary key of B as foreign of A
● Or both of above can be shown for one to one relationship.

44. 2.3 M:N relationship
● For M:N relationship between A and B, we create a separate relation C
● Primary key of C is composite by consisting of primary key of each of two entities in the relationship
● Any non-key attributes associated with M:N relationship are included with relation C
Order
Order-number Order date promised date
3245 12th Jan 13th Jan
7856 15th April 18th April

45. M:N relationship (continue)
Order Line
Product

46. 2.4 Unary Relationships
● It is relationship between instances of single entity type
● It is also called recursive relationships
Emp-ID Name Birthdate Manager-ID
1 Gita 1996/04/04 2
2 Remo 1997/05/05 1

47. 3. Normalize the relations
->Relations created in step 1 and 2 have unnecessary redundancies so normalization is needed to make them well structured.
4. Merge the relation
After we have created relations from separate E-R diagrams, it may have redundancies, so we should merge these relations.
Example:EMPLOYEE 1
(Emp_ID, Name, Address)
EMPLOYEE 2
(Emp_ID,Name, Jobcode)
Above relation have redundancies, so relation after merging as follows;
EMPLOYEE
(Emp_ID, Name, Address, Jobcode)

48. Problems during merging
Synonyms
In some cases, two or more attributes may have different name but same meaning. For example: employee_ID and employee-number
During merge, agreement from users on single standardized name for attribute or choose a third name
Homonyms
attribute name that may have more than 1 meaning
eg:STUDENT1(s_id, Name, Address)
STUDENT2(s_id, Name, Phone, Address)
Address in student1 refers to campus address and that of student 2 refers to home address. So it can be resolved bySTUDENT(s_id, Name, Phone,
Campus_address, home_address)
Dependencies between non-keys
When two 3NF relations are merged to form single relation, dependencies between non-key may result.
eg:STUDENT1(s_id, major), STUDENT2(s_id, Advisor) It is merged to
STUDENT (s_id, major, advisor)

49. Problems during merging(cont…)
Class/Subclass:
class/subclass relation may be hidden user views or relations
eg:PATIENT1(pid, name, address, date, treated) PATIENT2(pid, room)
If there are two types of patient: inpatient and outpatient, it can’t be merged as room is only for inpatient
so class/subclass relation is created.
PATIENT(pid, name, address)
INPATIENT(pid, room)
OUTPATIENT(pid, date, treated)

50. REFERENCES
1. https://peda.net/kenya/css/subjects/computer-studies/form-three/driac2/data-
processing/fom
2. https://www.slideshare.net/VijayKumar271/file-organization
3. https://www.techwalla.com/articles/types-file-organization
4. http://csit.merospark.com/fourth-semester/transformation-e-r-diagram-
relations-suitable-examples/

51. THANK YOU
ANY QUERIES?