Chapter

Software Design

9.1 Introduction:

Design is the meaningful engineering representation of something that is to be built. In the software engineering context, design focuses on four major area of concern: data, architecture, interfaces and component. Once the software requirements have been analyzed and specified, software design is the first of three technical activities—design, code generation, and test—are required to build the and verify the software. After making Software Requirement Specification of the education for all, now we are in position to design the software. As discussed earlier data design is the backbone of any RDBMS product. So firstly, we are emphasizing on database design. The data design transforms the information domain model created during analysis into data structures that will be required to implement the software.

9.2 Database Design:

As we have discussed earlier about the under developing system, which is based on. Internet technologies So, our database will be centralized database which will run on SQLserver.

9.2.1Data Structure:

Data structure is a representation of the logical relationship among individual elements of data. Because the structure of information will invariably affect the final procedural design, data structure is as important as program structure of the representation of the software architecture. Data structure dictates the organization, method of access, degree of associatively and processing alternatives of the information.

9.2.1 Functional Dependencies:

The Functional dependencies (FD) are the consequence of the interrelationship among attributes of an entity represented by a relation or due to the relationship between entities that is also represented by a relation.

9.2.2 Normalization

Normalization is a technique used in RDBMS to decompose into table into two or more different tables to remove functional dependency as well as redundancy. The normalization has different form namely—First NF, Second NF, Third NF, BCNF and Fourth NF. The decomposition of the table should be in the manner that data should not be lost i.e. the union of the decomposed table should must give the actual table. Normalization is also necessary to maintain referential integrity. In our context, we used normalization technique up to a three NF as our project had much number of FDs and case of data redundancy.

9.2.3 Table Description

To keep record without any redundancy each entity is represented by an independent table in the database. A list of tables is depicted below.

Дата добавления: 2015-10-21