Detailed description of Software Requirement Design

Document directory

• Overall Design Composition
• Structure Design
• Software Configuration Management Process

Software Requirement Specification

It is written in the developer's language from the perspective of development. It is for the project proposal. After the project is formally established, the system analyst further investigates the project, writing the Software Requirement Specification/software requirement specification is the product of the project proposal.

Including content

 

Verification software is primarily required for verification

Consistency

Integrity

Validity

Reality

Hardware and software implementation

Overall Design (Outline Design)

Requirement analysis, what is done, complete the software requirement specification according to the user requirement specification, design is mainly to solve how to do.

The design phase is divided into two phases:

Overall Design

Overall Structure

Detailed Design

Internal Logic of each module

Overall Design Composition

System design phase

Structure Design Stage

System design phase

Specify specific system implementation plans

Structure Design Stage

Determine the system software structure

Database Design

Overall Design Document

General Design Specification

Database Design Specification

User Manual

Test Plan

Structure Design

Converts a DFD graph to a structure chart based on a structured analysis.

Module

Modular

 

Abstraction

Information Hiding

Independent modules

Cohesion

Closeness of modules

Coupling

Graphics tools

SC diagram (structure diagram)

 

Structured Design Process

Conversion from DFD diagram to structure diagram

 

 

 

Two types of data flow charts

Transaction type

Conversion Type

 

 

General Design Specification

 

Detailed Design (module design)

The purpose of the detailed design is to determine how to implement the system. Get a precise description of the target system. In this way, the description can be directly translated into a programming language and a write-fast program in the encoding stage.

Determine the algorithm of each module, determine the data organization of each module, design a test case for each module, and write detailed design instructions.

Structured Design

Top-down

Global first and local later

Use single-entry-out

Process Design Tools

Program flowchart

 

Not easy to represent data structures

N-S Diagram

Not against structured design

 

Pad diagram, Problem Analysis Diagram

Is a two-dimensional tree structure to represent the control flow

 

 

PLD hybrid language (process design language)

 

Decision tree

 

 

Discriminant table

 

Software Configuration Management Process

Configuration ID

Version and change control

Version Control is the core function of Software Configuration Management. It manages the changes and changes of various software entities and documents during the lifetime of the Software. Its main function is to record and track file changes.

Requirement Analysis

40-60% of the problems in software projects are rooted in the demand analysis stage.

Writing detailed requirements is important and difficult.

The customer cannot clarify the requirement

Requirements change frequently

Incorrect understanding of analysts or customers

Main requirements

Business Requirements

User Requirements

System Requirements

Business requirements reflect the high-level objectives and requirements of the Organization or customer on the system and products, which are described in the project view and scope documents.

User requirements. This document describes the tasks that must be completed when you use the product.

System requirement definition the developer must be the first software function and the constraint on the first system

The requirement Project is a process, including requirement acquisition, requirement analysis, Requirement Specification Description, requirement verification, and requirement management.

Before the analysis stage ends, the specification description may have started. Once the basic problems and requirements of the problem domain are determined, the outline of the system is displayed.

 

Requirement verification means

Demand Review

Requirement Test

Requirement management includes

Change control

Version Control and requirement tracking

Structured Analysis Method

DFD)

In the data flow analysis method of the buxiang, the data model of the system is characterized by the E-R diagram of the object contact diagram.

In the data stream-oriented analysis method, the State Transition Graph STG depicts the system behavior model.

The following three models are created in the structured analysis method:

Function model data flow diagram implementation

Data Model E-R diagram implementation

Behavior Model Status transition diagram

Data Stream-oriented analysis methods

Is a modeling technology.

The main idea is to gradually refine, abstract, and decompose from top to bottom.

The core is that data dictionary is centered around this core. Three data flow charts (DFD, function model), Entity Relationship Diagram (ERD, data model), and State Migration diagram (STD, behavior Model)

Data Flow Diagram

The hierarchical data flow diagram only expresses the system decomposition. In order to fully describe the system, you must use the data dictionary to explain each data and processing in the diagram.

Data Dictionary,

In order to facilitate system query, understanding, and final implementation, the data dictionary needs to define three types of entries, namely data flow, data storage, and data items, which appear in the data flow diagram.