Database Development Life Cycle

Junaid Ul Hassan Qurtuba University Peshawar 1

Assignment# 1Previous Lectures

Discuss Centralized, De-Centralized Distributed Databases


Database Development Life cycle

Before discussing this system we should know why most of the projects fail?

A special interest Group concerned with organizational Aspects of IT, reached the following conclusions about software project.


Conclusion

80-90 % don’t meet their performance goals.About 80% are delivered late.About 40% fail.10-20 % meet all their success criteria.

There are several reasons for this failure.


These reasons are.

Lack of a complete Requirements specification

Lack of an appropriate development strategy

Poor Decomposition of a system that is hard to be manage.


Conti.

To solve these problems, A structured/ Systematic approach is developed for the development of Software system, which is called Information Life cycle or SDLC (Software Development life cycle).

So we can say that SDLC is a step by step approach towards development of Software related system.


Phases involve in SDLC

Database Planning Requirements Gathering & Analysis Designing Coding TestingMaintenance

we Discuss one by one.


Database Planning

Software Project planning is a set of activities that are usually adopted before the beginning of software development.

Database planning include the development of standards that govern how data will be collected, how format should be specified, what necessary documentation will be needed, how design and implementation should proceed.


Requirements Gathering & Analysis

After planning if you are ready to develop a database system. Then u will analyze the organization for whom u are going to develop a database. So what should be done in analysis phase?

Remember that in analysis phase the Analyst studies the organization that what are the requirements of organization


Conti.

So we can define analysis phase as: The process of collecting and analyzing

information about organization. This is the first mandatory phase of

database development process. Simply we can say that here analyst

gathers( collect) information about organization.


Conti.

Who is Analyst? The person who collects information is

called analyst. The analyst uses different techniques to

collect information's from users of an organization. Those techniques are called Fact-Finding Techniques.

Lets have a look of those techniques.


Fact- Finding Techniques

The methods use to capture information from a users are called Fact-finding techniques.

Different types of Fact-finding techniques.


Types of Fact-finding Techniques

1. Interviewing: Interviewing is the most commonly

used, and normally most useful, fact-finding techniques.

In this technique analyst can interview to collect information’s from individual (each user) face-to-face.


Conti.

There are two types of interview. Unstructured interview: in such kind of

interview interviewer can ask a general( specific) questions from interviewee.

While in structured Interview the interviewer can asks different questions depending on response of interviewee.


Advantages & Disadvantages of Interviewing

Advantages Allow interviewee to respond freely

and openly to questions .Allow interviewee to feel part of

project.Allow interviewer to reword question

during interview.


conti.

Disadvantages. it takes too much time to take interview

of more users. it means that it waste a lot of time.

Success is dependent on communication skills of interview.

Success can be dependent on willingness of interviewees to participate in interview.


2. Observation

In this technique an analyst himself/herself participate in organization activities.

It is possible to either participate in, or watch (observe) , a person perform activities to learn about system. This method is useful when the validity of data collected through other methods is difficult.


Conti.

Advantages Allows the validity of data to be checked. Observer can see exactly what is being

done. Relatively inexpensive.


Disadvantages

People may knowingly or unknowingly perform differently when being observed.

Some tasks may not always be performed in the manner in which they are observed.


3. Questionnaires

This is another Fact-Finding technique to conduct surveys through questionnaires.

In this method analyst prepare MCQ type questions and distributed among organizational users.

It has of two types.1) Free-Format questions:

This format offers the respondent greater freedom to answer the question. In this method Question is asked and a free space is given after that question and users have to write the answer in that free space.


2. Fixed Format Questionnaires

In this method an options are given along each question and users have to choose a specific option.


Advantages of Questionnaires

People can complete and return questionnaires at their convenience.

Relatively inexpensive way to gather data from a large number of people.

Reponses can be tabulated and analyzed quickly.


Disadvantages

Questionnaires may be returned incomplete.

Can not analyze and observe the respondent's body language.


Design Phase

• In this phase a “blueprint” of a software is constructing. This “blueprint” depicts a holistic (complete) view of a software.

• After collecting information’s about organization we should present that information’s in some specific way so that we can easily understand the meaning of data.


Conti.

Therefore Design phase is divided into sub phases which are as follow:

Conceptual Design:This is the graphical representation of data collected in analysis phase.It means that here designer construct specific models (ERD, DFD,STD ect) in order to represent the of an organization.


Conti.

The data model is built using the information’s documented in requirement phase.

Remember that conceptual design is completely independent of implementation details and target DBMS.

It means that here it will not be cleared/discussed that how can we implement it. It is only graphical representation of data of organization.


Logical Database Design

In this phase of designing the conceptual data model (design) will be converted into some specific model which is either based on relational data model or hierarchal or network data model.

Simply we can say that here we choose any specific data model. Explain it-----------------------------------------------


Physical Database Design

This is the third phase of designing phase. This is the final phase of the database design

process during this phase designers decide that how the database is to be implemented.

The last two phases of design phase are independent from physical consideration of DBMS but in this phase we have to choose a specific DBMS.

Here we describe that how data can be stored, how data can be retrieved etc.


Coding

This is the 4th phase of database development life cycle.

It is also called implementation phase. Here in this phase programmer writes program in computer languages in order to develop a database system.

The database implementation is achieved through DDL (Data Definition language) DBMS.


Testing

This is 5th phase of Database Development life cycle.

What is Testing? Testing means to find out errors in a program

while debugging means to correct error and then run that program.

So when we develop a database system after development we will test it that whether is it according to user’s requirements or not and is it working properly etc.


Maintenance

Maintenance means “ when we bring changes in old software will these changes can be accommodated easily”.

If we have brought changes in old software and it doesn’t affect on it then we can say that it is highly maintainable software otherwise not.


Any Question’s

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Database Development Life Cycle

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