Overview of projects carried out

First, the software development life cycle

Software Development Life Cycle (Software Development LifeCycle) refers to the production of software the whole process until maturity. It describes the software from the program, demand has begun, through analysis and design, code implementation, testing, deployment, on-line, maintenance, gradually until the final demise of the process.

• Market analysis, feasibility studies, project definition
• Requirements Analysis: figuring out "to solve the problem."
• design
  • Summary of design: to figure out "the overall implementation"
    • Division module, assign tasks, defining the relationship between calls
    • SUMMARY design documents mainly includes hierarchical data flow diagram, a structure diagram, data dictionary, and the corresponding text descriptions
    • To outline design document as the basis for the detailed design for each module
  • Detailed design: to figure out "how to do each of the modules."
    • Each module can be divided to different people to parallel design
    • Designers work object is a module, according to the outline design tasks given to local and external interfaces, module design and express algorithms, processes, state transitions and other content
    • The most important part of the document is a flowchart illustrating the detailed design modules, state diagrams, local variables and the corresponding text descriptions
• Coding
• Test: describe a software used to facilitate the identification of correctness, completeness, safety and quality of the process
• Operation and Maintenance
• Waste (eliminated)

Second, the need to analyze

1, the concept of

Requirements analysis, also known as software requirements analysis, system analysis needs analysis or requirements engineering, is a developer of an intensive research and analysis, an accurate understanding of the specific requirements of the user and project features, performance, reliability, etc., in the form of non-users demand expressed into a complete requirements definition, to determine what the system must do the process.

Simply put, developers treat system development (software) what to do to solve the problem and achieve a comprehensive description of what the function.

2, capture requirements

• Discussion with customers
• Field observations
• Questionnaire
• Access to information

Put themselves into imaginary customers

3, the output

Clear, standardized "software requirements specifications." Text, tables, diagrams and prototypes related graphics, illustrated, easy to understand user and development team.

• Business need: organizations or high levels of customer goals. Solve practical problems users, seeking to maximize the commercial viability and interests. Such as: In order to purchase information technology management and maintenance.
• User needs: a user's goal, or the user requires the system must be able to complete the task. Use case, the scene description and event - in response to the needs of the user table is an effective way to expression. Such as: View release movies, tickets and so on.
• Functional Requirements: provisions developer must implement software features in the product (ie describing what developers need to implement), a developer needs to complete the user by implementing features to suit your business. Such as: Before you purchase, you should first see the movie information (fares, film critic), select the video room, whether concessions.
• Non-functional requirements
  • Performance requirements
  • Environmental needs
  • Safety requirements
  • User interface requirements
  • Other requirements etc.

Clear customer demand, to ensure consistency, without ambiguity, otherwise increased development costs

Third, with the embodiment of FIG.

1, the concept of

Description System From a user perspective, and indicate that the operator of each function.

2, composition

1) Participants: a group of people interacting with the system, organization, equipment or external software components. Such as: customers, restaurants, suppliers, physical systems, parties and other payment authorization. Graphics is a villain

2) Example: indicates the operation of one or more participants to achieve specific goals executed. Such as: ordering, updating the menu, processing payments. Elliptical pattern.

3) association: association between this embodiment and the parameters were used. Graphics is a straight line.

4) System: The system may be a complete application, it can be a small software components that can be deployed on multiple computers and devices of large-scale distributed applications suite. Such as: "ordering website", "room service", "website version 2." Graphics are: rectangle.

5) Relationship

• Expanded relationship: a representation may be extended to another use case. Use case usually implies a selective expansion process.
• Relationship comprising: shows an embodiment comprising a further functional behavior of a use case.

Fourth, functional decomposition

The system is classified as a plurality of functional modules. Each function may also be divided into several sub-functions and interfaces, functions continue decomposition. You can get the prototype of the system, ie functional decomposition - function, sub-function, function interface.

V. Database design: ER diagram

1, the design process

First: to collect information

BBS forum's basic functions:

User registration and login, back-end database needs to store information and online registration status information of the user;

Users posting, posting back-end database needs to store information such as postings, titles, etc.;

Forum Management Forum: Forum background database needs to store various information, such as moderator, forum name, number and other posts;

Second: identify objects (entities, entity object)

The same feature abstract data, it may be a real object, it may be an abstract concept.

• user
• Main post
• Huitie
• Module

Third: identity property

Feature is used to describe an entity, characteristics, information or data.

• user
  • Account <primary key>
  • ID card
  • mobile phone number
  • nickname
  • password
  • e-mail
  • birthday
  • gender
  • User rating
  • Remarks Information
  • Date of registration
  • status
  • integral
• Main post
  • Posted people <foreign key>
  • Posted expression
  • Number of responses
  • title
  • text
  • Posted Time
  • Hits
  • status
  • Last reply time
• Huitie
  • Posts Number
  • Huitie people
  • Huitie expression
  • title
  • text
  • Huitie time
  • Hits
• Forum
  • Section name
  • Moderators
  • Excerpts motto
  • Click to rate
  • Posts

Fourth: the relationship between the identity object

Relationship: describe the links between entities and entity relationship between the three main

Decide whether to set up two tables foreign key primary

• One to One
  • 1:1
  • Commodity basic information: Product Details, husband: wife
• 1 to many
  • 1:M 、 1:N 、 1:*
  • Class - Students
• Many to many
  • M:N 、* :*
  • Professional Courses

Fifth: Draw ER diagrams

• Entity: Rectangle (usually a noun)
• Properties: oval (typically noun)
• Relationship: diamonds (typically a verb, there are three described)
• Connection: linear (arrow)

Sixth: The ER diagram into a data table (table)

1. To convert the entity name to the table name
2. Converting the attribute field of the table
3. Identifies the primary key
4. Relationship (foreign key) between the identity table

Candidate Key: In the table that uniquely identifies records related fields, namely: account number, ID, phone number

Main keywords: candidate keys, select a field as the primary identifier, account

Public Keywords: between two tables, there is the same sense of field, account number - Posted people

External keyword: public keyword, if a primary key field, the other foreign key fields

Unique key: the candidate keyword selection, to ensure data uniqueness

7: Use standardized data tables paradigm

2, case

The basic functions of lending management system

After the user registration and login, user registration information stored in the database of
a database to store details of all books
after the user library, borrowing information stored in the database of users, such as: time library, library information, user information and other
user also books later, time database information stored in restitution

Requirements: According to the above described demand, rendering E-R diagram, and using T-SQL definition of related tables, each table to be entered at least three records.

3, paradigm

1) concept

规范化数据（表）

2) Objective

• Redundancy in order to "eliminate" data
• "Eliminate" CRUD exception

3) classification

• The first paradigm: to ensure that each row can not be divided (atomicity)

• The second paradigm: Make sure the table each column and the primary key related (to ensure a table describe only one thing)

• The third paradigm: to ensure that all primary key columns, and each column is directly related to, rather than indirectly related

Note: Sometimes for performance and efficiency, they can give the constraint paradigm.

Sixth, draw a prototype map

Quickly understand the needs, iterative development.

Version update, backup.

Plotting prototype drawing by VS.

Seven, team development

• Version Control Tools
  • Subversion (SVN): Centralized management
  • Git: Distributed Management
• The original method
  • Naming conventions
  • Constraint Rule