1. 08. Ankita
14. Ashutosh
18. Samiksha
19. Laksh

2.  A data flow diagram (i.e. DFD) is a graphical system
model that shows all of the main requirements for an
information system in one diagram: inputs and
outputs , processes and data storage.
 Process
 Data Flow
 Data store
 External Agent
 Real Time Link

3.  Processes should be named and numbered for easy
references.
 The direction of flow is from top to bottom and left to right.
 When a process is exploded into lower level details they are
numbered PHYSICAL and LOGICAL DFDs.
 Readable
 Internally Consistent
 Accurately represents system requirements.
 Minimizing complexity
1. 7+-2 (Miller’s number)
2. Interface minimization
 Data flow consistency

4. A data dictionary is a structured repository of data about data.
The three classes of items to be defined in data
dictionary are as follows:
 Data Element:
The smallest unit of data that provides for no further
decomposition.
 Data Structure:
A group of data elements handled as a unit.
 Data Flow & Data Store:
Data flows are data structures in motion, whereas data stores
are data structures at rest.

11.  An event is some change or activity that takes place in the user’s
environment that stimulates a response from the software
system
 An event-response table (also called an event table or an event
list) lists all such events and the behavior the system is expected
to exhibit in reaction to each event.

12. # Event Table #
Event: An event which causes the system to do something.
Trigger: A signal that tells the system that an event has occurred,
either the arrival of data needing processing or a point in time.
Source: the source of an event (an actor for an EE and the system for
a TIE and CIE).
Activity: Behaviour that the system performs when an event occurs.
Response:An output, produced by the system, that goes to a
destination
Destination: An actor that receive the result of an
event execution
Event Trigger Source Activity Response Destination

13. In the event table, there are three types of events, that is:
1. External Event (EE): an event that occurs outside of the system,
usually initiated by external actor or user;
For example:
Student wants to search for a book item.
2. Temporal Internal Event (TIE): an event that happens when the system
reaches a specific point of time;
For example:
time to print book items report.
3. Conditional Internal Event (CIE): an event occurs when something
happens inside the system and the system must initiate some process
to response for this event;
For example:
student reordered new books when the reordered point is reached.

14. Example (student wants to search for a book item) and for an EE, we can
split this event into three main parts:
Student- Source
EE Search- Action
Book item-affected object
The TIE example (time to print book items report) can be divided into
three main parts as the following:
Time or "System"- Source
TIE Print- Action
Book item- Affected object
Finally, we can split the CIE (student reordered new books when the
reordered point is reached) into the following three main parts:
Student - Source
CIE Reordered- Action "if the reordered point is reached"
Book item- Affected object

15. Event Trigger Source Activity Response Destination
Customer
contacts
Owner
Contact
request Customer
Personal/Tele
-Contact
Meet/Receive
Call
Owner
Customer
booked
Vehicle
Rent a
Vehicle
request
Customer Personal/Tele
-Contact
Vehicle
approved
Owner
Owner
contact’s
Driver
Work
request
Owner Personal/Tele
-Contact
Drive/will not
Drive.
Driver
Owner
contacts
Agent
Contact
request
Owner Tele-Contact Request fulfilled Agent
Owner ask
for
Payment
Payment
request
Owner Payment by
Cash/Cheque
Full/Partial
Payment Done
Customer
Driver ask
contact
Details
Details
request
Driver Personal/Tele
-Contact
Give Contact
Details
Customer
Driver ask
payment
Payment
request
Driver Payment by
Cash/Cheque
Full payment
Done
Owner
-: Event Table of a Travels Business :-

16.  Event table defining functional requirements to
Traditional Approach model, Data Flow Diagrams
 The DFD integrates the Event table and the ERD
 When event gets triggered(input) the data flow
into system has to respond(output)
 External gents, data flow, & the process come from
DFD about the event is place in event table

17.  An event table is used to create a data flow
diagram by analyzing each event and the
data used and produced by the event
 Every row in an event table represents a data
flow diagram fragment and is used to create
a single process on a data flow diagram