SRSP (Project of Information System) Chapter-2

2.7.5   DATA BASE DESIGN

For storage purpose database is used, which is created in Visual Basics and Oracle. The purpose of this design technique is to transform the information models that were developed during analysis to models that conform to the target technology. The major objective of database design was to map the conceptual data model to an implementation model that a particular DBMS can process with performance that is acceptable to all users throughout the organization. Database design can be divided into the following two phases:

Logical database design

The process of mapping the conceptual data model to structures that are specific to the target DBMS. In other words it is the process of transforming the conceptual data model into a logical database model. There are four major logical database models in use today. These Include:

Ø      Hierarchical Data Model

Ø      Network Data Model

Ø      Relational Data Model         

Ø      Object-oriented data Model

I have chosen the relational data model for this project, because of two reasons. First, the relational data model in most commonly used in contemporary database applications. Second, some of the principles of logical database design for the relational model apply to the other logical models as well.

Relational Model

The relational model represents data in the form of tables called "Relations". Each relation consists of a set of named columns and arbitrary number of unnamed rows. The Entity Relationship Diagrams arc shown in Appendix B.

   Relationships

Depending on the optional of the relationship, the entities are either combined or the primary key of one entity type is placed as a foreign key in the other relation.

All relationships are further described by words or symbols that indicate the number of occurrences of one entity that can exist for a single occurrence of the related entity, and vice versa. There are three general possibilities.

• One-to-one (1 - 1) for one occurrence of the first entity there can exist only one related occurrence of the second entity occurrence of the second entity and vice versa.
• One –to – many (1 - M or M - 1) for one occurrence of one entity there can exist many related occurrences of a second entity; it doesn’t matter which is first or second.
• Many –to -many (M - M) for occurrence of the first entity, there can exist many related occurrence of the occurrence of the second entity there can exist many occurrences of the first entity.

Normalization

Normalization is the process of decomposing a relation with anomalies to produce smaller. Well-structured relations.

First Normal Form: - The first step in data analysis is to places each entity into first normal form. Simply stated, an entity is in INF if there are no elements or group of elements that repeat for a single occurrence of separate entity, possibly an entity that we haven’t yet defined in our data model.

All other entities that did not have repeating groups of elements are, by default, already in 1NF.

Second Normal Form: - The next step in data analysis is to place the entities in second normal form. It is assumed that you have already placed all entities into 1NF. An entity is in 2NF if it has a combination key and the full key, not part of it, derives all non-key elements. This concept is easer to demonstrate than to explain.

Third Normal Form: - We can further simplify our entities by placing them into 3NF. Entities must be in 2NF before beginning 3 NF analyses An entity is in 3NF if the values of its non-key elements are not dependent on any other non-key elements are not dependent the definition.

2.7.5  SYSTEM CONSTRUCTION/ ACQUISITION

1. Front end tools used:

Oracle developer 6i is used for forms and reports.

2. Back end tools used:

Visual Basic is used as a back end tool.

3. Hardware used/ purchased:

I used PIII for system construction.   (Intel 815 motherboard

Ram 128mb

Hard disk 20Gp

Monitor 15 inches digital

Keyboard & mouse Standard

CD Rom 52x)

4. Software used/ installed:

The software used in the system construction is as follows:

Windows 2000,

Visual Basic,

Oracle 8.0.5,

Office 2000.

5. Application is purchased from third party or coded:

All the applications are purchased from the retail stores.

2.7.6  SYTEM IMPLEMENTATION

PLANING FOR IMPLEMENTATION

Sometimes organizations hire a complete team for the implementation of the project. Thus this approach also requires a separate post. Later on only the relevant personnel are responsible for the whole ups and downs. Here in this case as the project is not too big. Though we have not used pure strategies of implementation, but tried to implement our software in the organization under "Parallel Approach" of the implementation. Implementation of a large system may take much time and so can't be approached in haphazard way.

It will be important to discuss about the three main approaches of implementation that I tested but used "Parallel Approach". These three methods for implementation are discussed as follow,

Direct change over

In the direct change over approach the old manual system at once replaced by the new computerized system. This approach could be risky as the old system is seized, its functionality totally get stop and new system is implemented without keeping in mind either it will work properly or not. If the new systems do not work properly then the transaction of that duration may lose.

OLD SYSTEM

NEW SYSTEM

Figure a

Phased Implementation

In Phased implementation the new system is introduced in modules and the old one if is removed in the same manner. This is best approach for the implementation but it could also be risky because of managing a data entry clerk in to jobs parallel. So I decided to use the Parallel Approach for the implementation of the system.

NEW System. OLD System.

Figure b

Parallel Running

In Parallel Running approach both systems (New computerized system & Old system) works side by side. Though this process increases the company overhead, as the organization requires extra men power. I discussed this approach to the management of our organization and told them about its plus points. Hence J decided to use this approach for the implementation of software until all the data has not been entered.

OLD System

Figure c

NEW System

IMPLEMENTATION OF SYSTEM

In   the   lines   to   follow   the   activities   involved   in   conversion   and implementation will be discussed. Although data conversion is important enough to be examined in detail, it forms only a part of the entire effort required to bring a new system into operation. Unlike most of the activities which have been discussed prior. The activities involved in starting up a new system will have a major impact on current operations. Without very careful control throughout the implementation phase, there may be a disastrous impact on the organization. But this system is designed in a way that no major staff is needed. The staff him self can operate the system designed. That's why there is no need for hiring new technical staff. It provides a user-friendly environment.

2.7.7  SYSTEM EVALUATION

The software is tested and evaluated by Project MANAGER. First it was tested with dummy data and then with the real data. The system was checked for all validations checks. All the searches were also tested. Project MANAGER, and other staff members appreciate the software. The software is handed over to the end users and they are given training so that they may be able to use it easily.

TRAINING TO THE END-USER:

After the accomplishment of the software, it was implemented after testing it with the dummy data. After the implementation training was given to the end users. End-user is trained about the entering of data, searching of data, viewing of data and printing of data. And then the entries were made with the actual data, during the training.