# Database design of computer room charge system

Objective

A period of time to participate in self-examination, to test the principles of the database, in which also more understanding of a lot of database problems. For example, how to create a good database, how to create a database.

                                   图一 数据库创建框架

Now start the Machine room reconstruction, formerly used is Brother Siang design database, now found themselves can also design out, so, according to this step to design a computer room charge system database.

First, planning

Because the computer room charge system is the second time to do, so in the overall planning stage it is easy to see the system in technology, economy, efficiency, law is feasible; The goal is to better match the application of reasonable operation.

Second, demand analysis

This stage is for the computer personnel (System analyst) and the user to jointly collect the information content of the database and the user's needs for processing. And in the form of requirements specification, as a guide to future system development and system verification basis.
In the computer room charge system, three kinds of permissions are assigned to users. The user can achieve different work performance.

                                 图二  机房收费系统功能框架

Third, conceptual design

Objective: A database conceptual structure that reflects the information needs of the user unit.
The conceptual pattern is independent of the computer hardware structure and is independent of the DBMS that supports the database.

E-r diagram of charge system in computer room

                                   图三  机房收费系统ER图

We can find entities that exist through ER diagrams and can be abstracted into tables.

Four, logical design

The main idea is to transform the conceptual model into a logical model that can be processed by DBMS. During the conversion process, the model is evaluated and the performance is tested in order to obtain a better pattern design.

In the computer room charge system, we can transform the ER diagram in the conceptual design into our logical model.

The relation mode of the charge system of computer room:

1) User information (user ID, user name, level, password, creator)

2) basic data (user number, member unit price, normal unit price, increment time, at least machine time, preparation time, minimum amount, edit date, edit time)

3) Student Information (school number, user ID, student name, gender, department, grade, class, remark, registration date, registration time)

4) Card (card number, user number, card status, card type, amount, whether checkout, registration time)

5) Recharge (card number, user number, recharge amount, recharge date)

6) on-Machine condition (card number, date of machine, machine time, machine date, machine time, consumption time, consumption amount, on-machine status)

7) return Card (card number, user number, refund amount, date of return)

8) Daily Checkout order (user number, previous balance, daily recharge amount, daily consumption, daily return, current amount, date)

9) Weekly Checkout order (user number, previous balance, daily recharge amount, daily consumption, daily return, current amount, date)

10) Working record (user number, machine time, machine time, machine number, user status)

Five, physical design

This stage is mainly in the database storage record format, storage record arrangement and access method. This phase relies entirely on a given hardware environment and database product.

No tables are designed as needed:

(1) User information (User_info)

Description	Field name	Data Type	size	is empty
User number	Userno	VarChar	10
User name	UserName	VarChar	10	Is
Level	Level	VarChar	10
Password	Password	VarChar	10
Created by	Constuctorno	VarChar	10	Is

(2) basic data (Basicdata_info)

Description	Field name	Data Type	size	is empty
User number	Userno	VarChar	10
Member Price	Viprate	Int
Normal unit Price	Commonrate	Int
Increment time	Increasetime	Int
Minimum on-Machine	Leasttime	Int
Preparation time	Readytime	Int
Minimum Amount	Leastcash	Int
Edit Date Time	SetDateTime	Datatime		Is

(3) Student Information (student_info)

Description	Field name	Data Type	size	is empty
User number	Userno	VarChar	10
School Number	Studentno	VarChar	10
Student Name	Studentname	VarChar	10
Gender	Sex	VarChar	10
Department	Department	VarChar	10
Grade	Grade	VarChar	10
Class	Class	VarChar	10
Note	Explain	VarChar	50	Is
Registration time	Registerdatetime	Datatime		Is
Student Status	Studentstate	VarChar	10	Is
Card	Cardno	VarChar	10

(4) Recharge (Recharge_info)

Description	Field name	Data Type	size	is empty
Card	Cardno	VarChar	10
User number	Userno	VarChar	10
Recharge Time	Rechargedatetime	Datatime
Recharge Amount	Recharge	Int

(5) on-Machine condition (online_info)

Description	Field name	Data Type	size	is empty
Card	Cardno	VarChar	10
Between the machines	Oncomdatetime	Datatime
Off-Machine time	Offcomdatetime	Datatime
Consumption time	Usetime	Int
Consumption amount	Usedcost	Int
On-Machine status	Comstate	varchar	10
Computer name	Comname	Int

(6) Return card (Backcard_info)

Description	Field name	Data Type	size	is empty
Card	Cardno	VarChar	10
User number	Userno	VarChar	10
Card return time	Backdatetime	Datatime
Return card Amount	Backcash	Int

(7) Card (Card_info)

Description	Field name	Data Type	size	is empty
Card	Cardno	VarChar	10
User number	Userno	varchar	10
Balance	Cash	Int		Is
Card type	Cardtype	varchar	10
Checkout	Ischeck	varchar	10
Registration time	Registerdatetime	Datetime
Card status	Cardstate	varchar	10

(8) Working record (Worklog_info)

Description	Field name	Data Type	size	is empty
User number	Userno	VarChar	10
Between the machines	Entercomdatetime	Datetime
Off-Machine time	Offcomdatetime	Datetime		Is
Computer name	Comname	varchar	50
User status	UserState	varchar	10

(9) Daily closing order (Daycheck_info)

Description	Field name	Data Type	size	is empty
User number	Userno	VarChar	10
Balance of previous Period	Remaincash	Int		Is
Same-day recharge amount	Rechargecash	Int		Is
Daily consumption	Consumecash	Int		Is
Same day refund	Backcash	Int		Is
Today's Amount	Allcash	Int		Is
Date	Checkdate	Date

(10) weekly closing order (Weekcheck_info)

Description	Field name	Data Type	size	is empty
User number	Userno	VarChar	10
Last week balance	Remaincash	Int		Is
Amount to recharge this week	Rechargecash	Int		Is
Spending this week	Consumecash	Int		Is
return this week	Backcash	Int		Is
Amount this week	Allcash	Int		Is
Date	Checkdate	Date

VI. implementation of the database

Set up the table after the basic completed, this time the database and the application to communicate, reference the database, the database test run.

Vii. database operation and Maintenance

In the process of writing the program, it is found that some local database data types will have an impact, can be updated changes. Maintain the database.

< extra > Chicken Soup for the Soul

Through the design of the database, I again go through the software creation process, the basic and soft work of the idea is the same, which still needs our constant understanding of continuous innovation, for example, the ER diagram of the drawing, how to find the entity, how to find out the relationship, this is the stage we have to master, this is our foundation!

"Wang Lei Http://blog.csdn.net/kisscatforever"

# Database design of computer room charge system