SDLC - Software Development Life Cycle Important Question Answer for IGNOU BCA MCA Students and other IT Students
What is data modeling? Give 5 examples for data modeling.
Data modeling is the act of exploring data-oriented structures. Like other modeling artifacts data
models can be used for a variety of purposes, from high-level conceptual models to physical data
models. From the point of view of an object-oriented developer, data modeling is conceptually
similar to class modeling. With data modeling you identify entity types whereas with class modeling
you identify classes. Data attributes are assigned to entity types just as you would assign
attributes and operations to classes.
Examples for data modeling include:
• Entity-Relationship diagrams
• Entity-Definition reports
• Entity and attributes report
• Table definition report
• Relationships, inheritance, composition and aggregation.
What is the difference between SRS document and design document? What are the
contents we should contain in the SRS document and design document.
SRS Document
SRS document is a contract between the development team and the customer. Once the SRS
document is approved by the customer, any subsequent controversies are settled by referring the
SRS document. SRS document defines the customer's requirements in terms of Functions,
performance, external interfaces and design constraints.
SRS Includes:
• Functional
• Non functional
• User
• Interface
• System
Design Document
The purpose of a design is to describe how the enhancements will be incorporated into the existing
project. It should contain samples of the finished product. This could include navigational
mechanism screenshots, example reports, and component diagrams.
Design Includes:
• E-R Diagrams
• Data flow diagrams
• Data Dictionary
Explain all the phases involved in the implementation phase.
Conduct system Test
In this test software packages and in – house programs have been installed and tested, we need to
conduct a final system test. All software packages, custom- built programs, and many existing
programs that comprise the new system must be tested to ensure that they all work together
This task involves analysts, owners, users, and builders.
Prepare Conversion Plan
On successful completion of system test, we can begin preparations to place the new system into
operation. Using the design specifications for the new system, the system analyst will develop a
detailed conversion plan. This plan will identify Database to be installed, end – user training and
documentation that needed to be developed, and a strategy for converting from the old system to
the new system. The conversion plan may include one of the following commonly used installation
strategies
1) Abrupt Cut-over
2) Parallel Conversion
3) Location Conversion
4) Staged Conversion
Install Databases
In the previous phase we built and tested the database. To place the system into operation we
need fully loaded databases. The purpose of this task is to populate the new systems databases
with existing database from the old system.
System builders play a primary role in this activity.
Train Users
Converting to a new system necessitates that system users be trained and provided with
documentation that guides them through using the new system. Training can be performed one on
one; however group training is preferred. This task will be completed by the system analysts and
involves system owners and users.
Convert to New System
Conversion to the new system from old system is a significant milestone. After conversion, the
ownership of the system officially transfers from the analysts and programmers to the end users.
The analyst completes this task by carrying out the conversion plan Recall that the conversion plan
includes detailed installation strategies to follow for converting from the existing to the new
production information system. This task involves the system owners, users, analysts, designers,
and builders.
List and explain different types of testing done during the testing phase.
Unit
Involves the design of test cases that validate that the internal program logic is functioning
properly, and that program inputs produce valid outputs. All decision branches and internal code
flow should be validated. Unit testing involves the use of debugging technology and testing
techniques at an application component level and is typically the responsibility of the developers,
not the QA staff.
Integration
As the system is integrated, it is tested by the system developer for specification compliance.
•Concerned with testing the system as it is integrated from its components
•Integration testing is normally the most expensive activity in the systems integration process
•Should focus on:
•Interface testing where the interactions between sub-systems and components are tested
•Property testing where system properties such as reliability, performance and usability are tested
System
Testing the system as a whole to validate that it meets its specification and the objectives of its
users. The testing of a complete system prior to delivery. The purpose of system testing is to
identify defects that will only surface when a complete system is assembled. That is, defects that
cannot be attributed to individual components or the interaction between two components. System
testing includes testing of performance, security, configuration sensitivity, startup and recovery
from failure modes. Involves test cases designed to validate that an application and its supporting
hardware/software components are properly processing business data and transactions. System
testing requires the use of regression testing techniques to validate that business functions are
meeting defined requirements.
Black Box
This is testing without knowledge of the internal workings of the item being tested. For example,
when black box testing is applied to software engineering, the tester would only know the "legal"
inputs and what the expected outputs should be, but not how the program actually arrives at those
outputs. It is because of this that black box testing can be considered testing with respect to the
specifications, no other knowledge of the program is necessary. For this reason, the tester and the
programmer can be independent of one another, avoiding programmer bias toward his own work.
White Box
Also known as glass box, structural, clear box and open box testing. White Box is a software
testing technique whereby explicit knowledge of the internal workings of the item being tested are
used to select the test data. Unlike Black Box testing, white box testing uses specific knowledge of
programming code to examine outputs. The test is accurate only if the tester knows what the
program is supposed to do. He or she can then see if the program diverges from its intended goal.
White box testing does not account for errors caused by omission, and all visible code must also be readable.
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